Update to 21.1.7

Relates: RHEL-130780 [DEV Task]: [RHEL9.8] Remove offload libraries from ppc64le Relates: RHEL-130783 [DEV Task]: clang use gcc-toolset-15 by default [rhel-9] Resolves: RHEL-108352 clang use gcc-toolset-15 by default [rhel-9] Resolves: RHEL-92552 [RHEL9.8] Remove offload libraries from ppc64le
2025-12-09 09:00:18 +00:00 · 2025-12-09 09:00:18 +00:00 · c6b19a3c95
commit c6b19a3c95
parent 9cb7e1045d
6 changed files with 1900 additions and 114 deletions
--- a/.gitignore
+++ b/.gitignore
@ -12,3 +12,4 @@
 /BUILDROOT
 /out
 /version.spec.inc
+/.gdbinit
--- a/0001-BPF-Support-Jump-Table-149715.patch
+++ b/0001-BPF-Support-Jump-Table-149715.patch
--- a/0001-SystemZ-Fix-ICE-with-i128-i64-uaddo-carry-chain.patch
+++ b/0001-SystemZ-Fix-ICE-with-i128-i64-uaddo-carry-chain.patch
@ -1,81 +0,0 @@
-From 6d5697f7cb4e933d2f176c46b7ac05a9cbaeb8b6 Mon Sep 17 00:00:00 2001
-From: Ulrich Weigand <ulrich.weigand@de.ibm.com>
-Date: Thu, 23 Jan 2025 19:11:18 +0100
-Subject: [PATCH] [SystemZ] Fix ICE with i128->i64 uaddo carry chain
-
-We can only optimize a uaddo_carry via specialized instruction
-if the carry was produced by another uaddo(_carry) instruction;
-there is already a check for that.
-
-However, i128 uaddo(_carry) use a completely different mechanism;
-they indicate carry in a vector register instead of the CC flag.
-Thus, we must also check that we don't mix those two - that check
-has been missing.
-
-Fixes: https://github.com/llvm/llvm-project/issues/124001
---
- .../Target/SystemZ/SystemZISelLowering.cpp    | 12 ++++++----
- llvm/test/CodeGen/SystemZ/pr124001.ll         | 23 +++++++++++++++++++
- 2 files changed, 31 insertions(+), 4 deletions(-)
- create mode 100644 llvm/test/CodeGen/SystemZ/pr124001.ll
-
-diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
-index 4040ab6d4510..1fb31c26e20d 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
-+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
-@@ -4708,15 +4708,19 @@ SDValue SystemZTargetLowering::lowerXALUO(SDValue Op,
- }
- 
- static bool isAddCarryChain(SDValue Carry) {
-  while (Carry.getOpcode() == ISD::UADDO_CARRY)
-+  while (Carry.getOpcode() == ISD::UADDO_CARRY &&
-+         Carry->getValueType(0) != MVT::i128)
-     Carry = Carry.getOperand(2);
-  return Carry.getOpcode() == ISD::UADDO;
-+  return Carry.getOpcode() == ISD::UADDO &&
-+         Carry->getValueType(0) != MVT::i128;
- }
- 
- static bool isSubBorrowChain(SDValue Carry) {
-  while (Carry.getOpcode() == ISD::USUBO_CARRY)
-+  while (Carry.getOpcode() == ISD::USUBO_CARRY &&
-+         Carry->getValueType(0) != MVT::i128)
-     Carry = Carry.getOperand(2);
-  return Carry.getOpcode() == ISD::USUBO;
-+  return Carry.getOpcode() == ISD::USUBO &&
-+         Carry->getValueType(0) != MVT::i128;
- }
- 
- // Lower UADDO_CARRY/USUBO_CARRY nodes.
-diff --git a/llvm/test/CodeGen/SystemZ/pr124001.ll b/llvm/test/CodeGen/SystemZ/pr124001.ll
-new file mode 100644
-index 000000000000..9cf630a55dd6
--- /dev/null
-+++ b/llvm/test/CodeGen/SystemZ/pr124001.ll
-@@ -0,0 +1,23 @@
-+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
-+; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z13 | FileCheck %s
-+
-+define i64 @test(i128 %in) {
-+; CHECK-LABEL: test:
-+; CHECK:       # %bb.0:
-+; CHECK-NEXT:    larl %r1, .LCPI0_0
-+; CHECK-NEXT:    vl %v0, 0(%r2), 3
-+; CHECK-NEXT:    vl %v1, 0(%r1), 3
-+; CHECK-NEXT:    vaccq %v0, %v0, %v1
-+; CHECK-NEXT:    vlgvg %r1, %v0, 1
-+; CHECK-NEXT:    la %r2, 1(%r1)
-+; CHECK-NEXT:    br %r14
-+  %1 = tail call { i128, i1 } @llvm.uadd.with.overflow.i128(i128 %in, i128 1)
-+  %2 = extractvalue { i128, i1 } %1, 1
-+  %3 = zext i1 %2 to i64
-+  %4 = add i64 %3, 1
-+  ret i64 %4
-+}
-+
-+declare { i128, i1 } @llvm.uadd.with.overflow.i128(i128, i128) #0
-+
-+attributes #0 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
-- 
-2.48.1
-
--- a/0002-BPF-Remove-unused-weak-symbol-__bpf_trap-166003.patch
+++ b/0002-BPF-Remove-unused-weak-symbol-__bpf_trap-166003.patch
@ -0,0 +1,130 @@
+From be4fa19ecf95d94d3ef46be183d3d4b4ebb6bb47 Mon Sep 17 00:00:00 2001
+From: yonghong-song <yhs@fb.com>
+Date: Mon, 3 Nov 2025 11:11:47 -0800
+Subject: [PATCH] [BPF] Remove unused weak symbol __bpf_trap (#166003)
+
+Nikita Popov reported an issue ([1]) where a dangling weak symbol
+__bpf_trap is in the final binary and this caused libbpf failing like
+below:
+
+  $ veristat -v ./t.o
+  Processing 't.o'...
+  libbpf: elf: skipping unrecognized data section(4) .eh_frame
+  libbpf: elf: skipping relo section(5) .rel.eh_frame for section(4) .eh_frame
+  libbpf: failed to find BTF for extern '__bpf_trap': -3
+  Failed to open './t.o': -3
+
+In llvm, the dag selection phase generates __bpf_trap in code. Later the
+UnreachableBlockElim pass removed __bpf_trap from the code, but
+__bpf_trap symbol survives in the symbol table.
+
+Having a dangling __bpf_trap weak symbol is not good for old kernels as
+seen in the above veristat failure. Although users could use compiler
+flag `-mllvm -bpf-disable-trap-unreachable` to workaround the issue,
+this patch fixed the issue by removing the dangling __bpf_trap.
+
+  [1] https://github.com/llvm/llvm-project/issues/165696
+
+(cherry picked from commit 8fd1bf2f8c9e6e7c4bc5f6915a9d52bb3672601b)
+---
+ llvm/lib/Target/BPF/BPFAsmPrinter.cpp | 24 ++++++++++++++++++++
+ llvm/lib/Target/BPF/BPFAsmPrinter.h   |  1 +
+ llvm/test/CodeGen/BPF/bpf_trap.ll     | 32 +++++++++++++++++++++++++++
+ 3 files changed, 57 insertions(+)
+ create mode 100644 llvm/test/CodeGen/BPF/bpf_trap.ll
+
+diff --git a/llvm/lib/Target/BPF/BPFAsmPrinter.cpp b/llvm/lib/Target/BPF/BPFAsmPrinter.cpp
+index 77dc4a75a7d6..b2a82040ee82 100644
+--- a/llvm/lib/Target/BPF/BPFAsmPrinter.cpp
+++ b/llvm/lib/Target/BPF/BPFAsmPrinter.cpp
+@@ -88,6 +88,16 @@ bool BPFAsmPrinter::doFinalization(Module &M) {
+     }
+   }
+ 
+  for (GlobalObject &GO : M.global_objects()) {
+    if (!GO.hasExternalWeakLinkage())
+      continue;
+
+    if (!SawTrapCall && GO.getName() == BPF_TRAP) {
+      GO.eraseFromParent();
+      break;
+    }
+  }
+
+   return AsmPrinter::doFinalization(M);
+ }
+ 
+@@ -160,6 +170,20 @@ bool BPFAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
+ }
+ 
+ void BPFAsmPrinter::emitInstruction(const MachineInstr *MI) {
+  if (MI->isCall()) {
+    for (const MachineOperand &Op : MI->operands()) {
+      if (Op.isGlobal()) {
+        if (const GlobalValue *GV = Op.getGlobal())
+          if (GV->getName() == BPF_TRAP)
+            SawTrapCall = true;
+      } else if (Op.isSymbol()) {
+        if (const MCSymbol *Sym = Op.getMCSymbol())
+          if (Sym->getName() == BPF_TRAP)
+            SawTrapCall = true;
+      }
+    }
+  }
+
+   BPF_MC::verifyInstructionPredicates(MI->getOpcode(),
+                                       getSubtargetInfo().getFeatureBits());
+ 
+diff --git a/llvm/lib/Target/BPF/BPFAsmPrinter.h b/llvm/lib/Target/BPF/BPFAsmPrinter.h
+index 0cfb2839c8ff..60a285ea2b7d 100644
+--- a/llvm/lib/Target/BPF/BPFAsmPrinter.h
+++ b/llvm/lib/Target/BPF/BPFAsmPrinter.h
+@@ -39,6 +39,7 @@ public:
+ private:
+   BTFDebug *BTF;
+   TargetMachine &TM;
+  bool SawTrapCall = false;
+ 
+   const BPFTargetMachine &getBTM() const;
+ };
+diff --git a/llvm/test/CodeGen/BPF/bpf_trap.ll b/llvm/test/CodeGen/BPF/bpf_trap.ll
+new file mode 100644
+index 000000000000..ab8df5ff7cb0
+--- /dev/null
+++ b/llvm/test/CodeGen/BPF/bpf_trap.ll
+@@ -0,0 +1,32 @@
+; RUN: llc < %s | FileCheck %s
+;
+target triple = "bpf"
+
+define i32 @test(i8 %x) {
+entry:
+  %0 = and i8 %x, 3
+  switch i8 %0, label %default.unreachable4 [
+    i8 0, label %return
+    i8 1, label %sw.bb1
+    i8 2, label %sw.bb2
+    i8 3, label %sw.bb3
+  ]
+
+sw.bb1:                                           ; preds = %entry
+  br label %return
+
+sw.bb2:                                           ; preds = %entry
+  br label %return
+
+sw.bb3:                                           ; preds = %entry
+  br label %return
+
+default.unreachable4:                             ; preds = %entry
+  unreachable
+
+return:                                           ; preds = %entry, %sw.bb3, %sw.bb2, %sw.bb1
+  %retval.0 = phi i32 [ 12, %sw.bb1 ], [ 43, %sw.bb2 ], [ 54, %sw.bb3 ], [ 32, %entry ]
+  ret i32 %retval.0
+}
+
+; CHECK-NOT: __bpf_trap
+-- 
+2.50.1
+
--- a/llvm.spec
+++ b/llvm.spec
@ -2,7 +2,7 @@
 #region version
 %global maj_ver 21
 %global min_ver 1
-%global patch_ver 3
+%global patch_ver 7
 #global rc_ver rc3

 %bcond_with snapshot_build
@ -19,6 +19,24 @@
  %bcond_with gold
 %endif

+# Enable this in order to disable a lot of features and get to clang as fast
+# as possible. This is useful in order to bisect issues affecting LLVM, clang
+# or LLD.
+%bcond_with fastclang
+%if %{with fastclang}
+%define bcond_override_default_lldb 0
+%define bcond_override_default_offload 0
+%define bcond_override_default_mlir 0
+%define bcond_override_default_flang 0
+%define bcond_override_default_build_bolt 0
+%define bcond_override_default_polly 0
+%define bcond_override_default_pgo 0
+%define bcond_override_default_libcxx 0
+%define bcond_override_default_lto_build 0
+%define bcond_override_default_check 0
+%define _find_debuginfo_dwz_opts %{nil}
+%endif
+
 # Build compat packages llvmN instead of main package for the current LLVM
 # version. Used on Fedora.
 %bcond_with compat_build
@ -49,16 +67,18 @@
 %else
 %bcond_without offload
 %endif
-%elifarch %{ix86}
+%else
+%ifarch %{ix86}
 # libomptarget is not supported on 32-bit systems.
 %bcond_with offload
 %else
 %bcond_without offload
 %endif
+%endif

 # MLIR version 22 started to require nanobind >= 2.9, which is only available
 # on Fedora >= 44.
-%if %{without compat_build} && ((%{maj_ver} >= 22 && 0%{?fedora} >= 44) || (%{maj_ver} < 22 && 0%{?fedora} >= 41))
+%if %{without compat_build} && %{defined fedora} && (%{maj_ver} < 22 || 0%{?fedora} >= 44)
 %ifarch %{ix86}
 %bcond_with mlir
 %else
@ -68,10 +88,69 @@
 %bcond_with mlir
 %endif

+#region flang
+%if %{without compat_build} && %{defined fedora} && (%{maj_ver} >= 22 && 0%{?fedora} >= 44)
+# Link error on i686.
+# s390x is not supported upstream yet.
+%ifarch i686 s390x
+%bcond_with flang
+%else
+%bcond_without flang
+%endif
+%endif
+
+%if %{with flang}
+
+# Sanity check for flang
+# flang depends on mlir, clang, flang, openmp.
+# Make sure those are being built.
+%if %{without mlir}
+%{error:flang must be built --with=mlir}
+%endif
+
+# Set Fortran build flags to nil because they contain flags that don't apply to flang.
+%global build_fflags %{nil}
+
+%{lua:
+
+-- Return the maximum number of parallel jobs a build can run based on the
+-- amount of maximum memory used per process (per_proc_mem).
+function print_max_procs(per_proc_mem)
+    local f = io.open("/proc/meminfo", "r")
+    local mem = 0
+    local nproc_str = nil
+    for line in f:lines() do
+        _, _, mem = string.find(line, "MemTotal:%s+(%d+)%s+kB")
+        if mem then
+           break
+        end
+    end
+    f:close()
+
+    local proc_handle = io.popen("nproc")
+    _, _, nproc_str = string.find(proc_handle:read("*a"), "(%d+)")
+    proc_handle:close()
+    local nproc = tonumber(nproc_str)
+    if nproc < 1 then
+        nproc = 1
+    end
+    local mem_mb = mem / 1024
+    local cpu = math.floor(mem_mb / per_proc_mem)
+    if cpu < 1 then
+        cpu = 1
+    end
+
+    if cpu > nproc then
+        cpu = nproc
+    end
+    print(cpu)
+end
+}
+%endif
+#endregion flang
+
 # The libcxx build condition also enables libcxxabi and libunwind.
-# Fedora 41 is the first version that enabled FatLTO for clang-built files.
-# Without FatLTO, we can't enable ThinLTO and link using GNU LD.
-%if %{without compat_build} && 0%{?fedora} >= 41
+%if %{without compat_build} && %{defined fedora}
 %bcond_without libcxx
 %else
 %bcond_with libcxx
@ -79,7 +158,7 @@

 # I've called the build condition "build_bolt" to indicate that this does not
 # necessarily "use" BOLT in order to build LLVM.
-%if %{without compat_build} && 0%{?fedora} >= 41
+%if %{without compat_build} && %{defined fedora}
 # BOLT only supports aarch64 and x86_64
 %ifarch aarch64 x86_64
 %bcond_without build_bolt
@ -90,7 +169,7 @@
 %bcond_with build_bolt
 %endif

-%if %{without compat_build} && 0%{?fedora} >= 41
+%if %{without compat_build} && %{defined fedora}
 %bcond_without polly
 %else
 %bcond_with polly
@ -131,8 +210,24 @@
 %ifarch %ix86 riscv64
 %bcond_with lto_build
 %else
+%if %{defined rhel} && 0%{?rhel} <= 8
+# LTO builds got enabled on Fedora and RHEL >= 9 only.
+%bcond_with lto_build
+%else
 %bcond_without lto_build
 %endif
+%endif
+
+# Historically, LLD was used used at the same combinations that enabled PGO.
+# If this changes, we need to update the following lines.
+# However, we should be able to link using LLD even if PGO is disabled.
+# Reminder: RHEL8 still builds with gcc + ld.bfd.
+%if %{with pgo}
+%bcond_without use_lld
+%else
+# RHEL8 still builds with gcc + ld.bfd.
+%bcond_with use_lld
+%endif

 # For PGO Disable LTO for now because of LLVMgold.so not found error
 # Use LLVM_ENABLE_LTO:BOOL=ON flags to enable LTO instead
@ -142,6 +237,7 @@

 # We are building with clang for faster/lower memory LTO builds.
 # See https://docs.fedoraproject.org/en-US/packaging-guidelines/#_compiler_macros
+# Reminder: This only works on Fedora and RHEL >= 9.
 %global toolchain clang

 # Make sure that we are not building with a newer compiler than the targeted
@ -158,8 +254,10 @@
 %global __cxx /usr/bin/clang++-%{host_clang_maj_ver}
 %endif

-%if %{defined rhel} && 0%{?rhel} < 10
-%global gts_version 14
+# The upper bound must remain and never exceed the latest RHEL version with GTS,
+# so that this does not apply to ELN or a brand new RHEL version.
+%if %{defined rhel} && 0%{?rhel} <= 10
+%global gts_version 15
 %endif

 %if %{defined rhel} && 0%{?rhel} <= 8
@ -314,6 +412,10 @@
 %endif
 #endregion PGO globals

+#region flang globals
+%global pkg_name_flang flang%{pkg_suffix}
+#endregion flang globals
+
 #endregion globals

 #region packages
@ -411,6 +513,12 @@ Patch2202: 0001-22-polly-shared-libs.patch
 #region RHEL patches
 # RHEL 8 only
 Patch501: 0001-Fix-page-size-constant-on-aarch64-and-ppc64le.patch
+# Backport a fix for https://github.com/llvm/llvm-project/issues/165696 from
+# LLVM 22. The first patch is a requirement of the second patch.
+# Apply the fix to RHEL8 only because the other distros do not need this fix
+# because they already support kfunc __bpf_trap.
+Patch502: 0001-BPF-Support-Jump-Table-149715.patch
+Patch503: 0002-BPF-Remove-unused-weak-symbol-__bpf_trap-166003.patch
 #endregion RHEL patches

 # Fix a pgo miscompilation triggered by building Rust 1.87 with pgo on ppc64le.
@ -438,6 +546,13 @@ Patch2201: 0001-clang-Add-a-hack-to-fix-the-offload-build-with-the-m.patch
 %global __python3 /usr/bin/python3.12
 %endif

+%if %{with fastclang}
+# fastclang depends on overriding default conditionals via
+# bcond_override_default which is only available on RPM 4.20 and newer.
+# More info:
+# https://rpm-software-management.github.io/rpm/manual/conditionalbuilds.html#overriding-defaults
+BuildRequires:	rpm >= 4.20
+%endif
 %if %{defined gts_version}
 # Required for 64-bit atomics on i686.
 BuildRequires: gcc-toolset-%{gts_version}-libatomic-devel
@ -483,6 +598,10 @@ BuildRequires:	python3-scipy
 %endif
 %endif

+%else
+%if %{with use_lld}
+BuildRequires:	lld
+%endif
 %endif

 # This intentionally does not use python3_pkgversion. RHEL 8 does not have
@ -571,7 +690,7 @@ BuildRequires: procps-ng
 # For reproducible pyc file generation
 # See https://docs.fedoraproject.org/en-US/packaging-guidelines/Python_Appendix/#_byte_compilation_reproducibility
 # Since Fedora 41 this happens automatically, and RHEL 8 does not support this.
-%if %{without compat_build} && ((%{defined fedora} && 0%{?fedora} < 41) || 0%{?rhel} == 9 || 0%{?rhel} == 10)
+%if %{without compat_build} && (0%{?rhel} == 9 || 0%{?rhel} == 10)
 BuildRequires: /usr/bin/marshalparser
 %global py_reproducible_pyc_path %{buildroot}%{python3_sitelib}
 %endif
@ -749,7 +868,11 @@ Requires: gcc-toolset-%{gts_version}-gcc-c++
 Recommends: %{pkg_name_compiler_rt}%{?_isa} = %{version}-%{release}
 Requires: %{pkg_name_llvm}-libs = %{version}-%{release}
 # atomic support is not part of compiler-rt
+%if %{defined gts_version}
+Recommends: gcc-toolset-%{gts_version}-libatomic-devel
+%else
 Recommends: libatomic%{?_isa}
+%endif
 # libomp-devel is required, so clang can find the omp.h header when compiling
 # with -fopenmp.
 Recommends: %{pkg_name_libomp}-devel%{_isa} = %{version}-%{release}
@ -1146,6 +1269,42 @@ Polly header files.
 %endif
 #endregion polly packages

+#region flang packages
+%if %{with flang}
+%package -n %{pkg_name_flang}
+Summary: a Fortran language front-end designed for integration with LLVM
+Requires: %{pkg_name_flang}-runtime%{?_isa} = %{version}-%{release}
+# flang installs headers in the clang resource directory
+Requires: %{pkg_name_clang}-resource-filesystem%{?_isa} = %{version}-%{release}
+# flang implicitly calls ld.bfd when linking and depends on the gcc runtime objects.
+Requires: binutils
+Requires: gcc
+# Up to version 17.0.6-1, flang used to provide a flang-devel package.
+# This changed in 17.0.6-2 and all development-related files are now
+# distributed in the main flang package.
+Obsoletes: %{pkg_name_flang}-devel < 17.0.6-2
+
+# We no longer ship flang-doc.
+Obsoletes: %{pkg_name_flang}-doc < 22
+
+License: Apache-2.0 WITH LLVM-exception
+URL:     https://flang.llvm.org
+
+%description -n %{pkg_name_flang}
+
+Flang is a ground-up implementation of a Fortran front end written in modern
+C++.
+
+%package -n %{pkg_name_flang}-runtime
+Summary: Flang runtime libraries
+Conflicts: %{pkg_name_flang} < 17.0.6-2
+
+%description -n %{pkg_name_flang}-runtime
+Flang runtime libraries.
+
+%endif
+#endregion flang packages
+
 #endregion packages

 #region prep
@ -1184,6 +1343,11 @@ Polly header files.

 %if %{defined rhel} && 0%{?rhel} == 8
 %patch -p1 -P501
+%if %{maj_ver} < 22
+# The following patches have been backported from LLVM 22.
+%patch -p1 -P502
+%patch -p1 -P503
+%endif
 %endif

 #region LLVM preparation
@ -1253,7 +1417,7 @@ cd llvm/utils/lit
 %ifarch %ix86
 %global reduce_debuginfo 1
 %endif
-%if 0%{?rhel} == 8
+%if 0%{?rhel} == 8 || %{with fastclang}
 %global reduce_debuginfo 1
 %endif

@ -1281,6 +1445,11 @@ cd llvm/utils/lit
 %global projects %{projects};polly
 %endif

+%if %{with flang}
+%global projects %{projects};flang
+%global runtimes %{runtimes};flang-rt
+%endif
+
 %if %{with libcxx}
 %global runtimes %{runtimes};libcxx;libcxxabi;libunwind
 %endif
@ -1289,7 +1458,10 @@ cd llvm/utils/lit
 %global runtimes %{runtimes};offload
 %endif

-%global cfg_file_content --gcc-triple=%{_target_cpu}-redhat-linux
+%global gcc_triple --gcc-triple=%{_target_cpu}-redhat-linux
+
+%global cfg_file_content %{gcc_triple}
+%global cfg_file_content_flang %{gcc_triple}

 # We want to use DWARF-5 on all snapshot builds.
 %if %{without snapshot_build} && %{defined rhel} && 0%{?rhel} < 10
@ -1373,6 +1545,11 @@ popd
    -DLLVM_ENABLE_EH=ON
 %endif

+%if %reduce_debuginfo == 1
+	%global cmake_common_args %{cmake_common_args} -DCMAKE_C_FLAGS_RELWITHDEBINFO="%{optflags} -DNDEBUG"
+	%global cmake_common_args %{cmake_common_args} -DCMAKE_CXX_FLAGS_RELWITHDEBINFO="%{optflags} -DNDEBUG"
+%endif
+
 %global cmake_config_args %{cmake_common_args}

 #region clang options
@ -1401,7 +1578,8 @@ popd
 #region compiler-rt options
 %global cmake_config_args %{cmake_config_args} \\\
 	-DCOMPILER_RT_INCLUDE_TESTS:BOOL=OFF \\\
-	-DCOMPILER_RT_INSTALL_PATH=%{_prefix}/lib/clang/%{maj_ver}
+	-DCOMPILER_RT_INSTALL_PATH=%{_prefix}/lib/clang/%{maj_ver} \\\
+	-DLLVM_BUILD_EXTERNAL_COMPILER_RT:BOOL=ON
 #endregion compiler-rt options

 #region docs options
@ -1469,7 +1647,6 @@ popd
 %global cmake_config_args %{cmake_config_args}  \\\
 	-DLLVM_APPEND_VC_REV:BOOL=OFF \\\
 	-DLLVM_BUILD_EXAMPLES:BOOL=OFF \\\
-	-DLLVM_BUILD_EXTERNAL_COMPILER_RT:BOOL=ON \\\
 	-DLLVM_BUILD_RUNTIME:BOOL=ON \\\
 	-DLLVM_BUILD_TOOLS:BOOL=ON \\\
 	-DLLVM_BUILD_UTILS:BOOL=ON \\\
@ -1502,6 +1679,7 @@ popd
        -DMLIR_INSTALL_AGGREGATE_OBJECTS=OFF \\\
        -DMLIR_BUILD_MLIR_C_DYLIB=ON \\\
        -DMLIR_ENABLE_BINDINGS_PYTHON:BOOL=ON
+
 %endif
 #endregion mlir options

@ -1538,6 +1716,23 @@ popd
 %endif
 #endregion polly options

+#region flang options
+%if %{with flang}
+%global cmake_config_args %{cmake_config_args} \\\
+  -DFLANG_INCLUDE_DOCS:BOOL=ON
+# Build both, shared and static flang runtime objects.
+# See also https://llvm.org/devmtg/2025-04/slides/quick_talk/kruse_flang-rt.pdf
+%global cmake_config_args %{cmake_config_args} \\\
+  -DFLANG_RT_ENABLE_SHARED:BOOL=ON \\\
+  -DFLANG_RT_ENABLE_STATIC:BOOL=ON
+# The amount of RAM used per process has been set by trial and error.
+# This number may increase/decrease from time to time and may require changes.
+# We prefer to be on the safe side in order to avoid spurious errors.
+%global cmake_config_args %{cmake_config_args} \\\
+  -DFLANG_PARALLEL_COMPILE_JOBS=%{lua: print_max_procs(3072)}
+%endif
+#endregion flang options
+

 #region test options
 %global cmake_config_args %{cmake_config_args} \\\
@ -1547,11 +1742,7 @@ popd
 	-DLLVM_LIT_ARGS="-vv"

 %if %{with lto_build}
-%if 0%{?fedora} >= 41
 	%global cmake_config_args %{cmake_config_args} -DLLVM_UNITTEST_LINK_FLAGS="-fno-lto"
-%else
-	%global cmake_config_args %{cmake_config_args} -DLLVM_UNITTEST_LINK_FLAGS="-Wl,-plugin-opt=O0"
-%endif
 %endif
 #endregion test options

@ -1579,11 +1770,6 @@ popd
 	%global cmake_config_args %{cmake_config_args} -DPPC_LINUX_DEFAULT_IEEELONGDOUBLE=ON
 %endif

-%if %reduce_debuginfo == 1
-	%global cmake_config_args %{cmake_config_args} -DCMAKE_C_FLAGS_RELWITHDEBINFO="%{optflags} -DNDEBUG"
-	%global cmake_config_args %{cmake_config_args} -DCMAKE_CXX_FLAGS_RELWITHDEBINFO="%{optflags} -DNDEBUG"
-%endif
-
 %if 0%{?__isa_bits} == 64
 	%global cmake_config_args %{cmake_config_args} -DLLVM_LIBDIR_SUFFIX=64
 %endif
@ -1609,7 +1795,11 @@ popd
 	# This option uses the NUMBER_OF_LOGICAL_CORES query in CMake which doesn't
 	# work on s390x.
 	# https://gitlab.kitware.com/cmake/cmake/-/issues/26619
-	%global cmake_config_args %{cmake_config_args} -DLLVM_RAM_PER_COMPILE_JOB=2048
+	# The value 4096 was used after we've seen cases of memory exhaustion on a
+	# system with 64GiB RAM and 16 jobs. It worked a few times after applied,
+	# but we can't guarantee it's enough. It's important to remember that RHEL8
+	# uses GCC. This value should not be applied to a build using clang.
+	%global cmake_config_args %{cmake_config_args} -DLLVM_RAM_PER_COMPILE_JOB=4096
 %endif
 %endif
 #endregion misc options
@ -1731,11 +1921,15 @@ cd $OLD_CWD
  # LLVM_VP_COUNTERS_PER_SITE instead of adding it, hence the
  # -DLLVM_VP_COUNTERS_PER_SITE=8.
  %global extra_cmake_opts %{extra_cmake_opts} -DLLVM_VP_COUNTERS_PER_SITE=8
+%endif
+
 %if 0%{with lto_build}
  %global extra_cmake_opts %{extra_cmake_opts} -DLLVM_ENABLE_LTO:BOOL=Thin
  %global extra_cmake_opts %{extra_cmake_opts} -DLLVM_ENABLE_FATLTO=ON
 %endif
-  %global extra_cmake_opts %{extra_cmake_opts} -DLLVM_USE_LINKER=lld
+
+%if 0%{with use_lld}
+%global extra_cmake_opts %{extra_cmake_opts} -DLLVM_USE_LINKER=lld
 %endif

 %cmake -G Ninja %{cmake_config_args} %{extra_cmake_opts} $extra_cmake_args
@ -1887,6 +2081,14 @@ popd

 %cmake_install

+%if %{with flang}
+# Create ld.so.conf.d entry
+mkdir -p %{buildroot}%{_sysconfdir}/ld.so.conf.d
+cat >> %{buildroot}%{_sysconfdir}/ld.so.conf.d/%{pkg_name_flang}-%{_arch}.conf << EOF
+%{_prefix}/lib/clang/%{maj_ver}/lib/%{llvm_triple}/
+EOF
+%endif
+
 popd

 mkdir -p %{buildroot}/%{_bindir}
@ -2066,7 +2268,8 @@ echo " %{cfg_file_content}" >> %{buildroot}%{_sysconfdir}/%{pkg_name_clang}/i386
 %ifarch ppc64le
 # Fix install path on ppc64le so that the directory name matches the triple used
 # by clang.
-mv %{buildroot}%{_prefix}/lib/clang/%{maj_ver}/lib/powerpc64le-redhat-linux-gnu %{buildroot}%{_prefix}/lib/clang/%{maj_ver}/lib/%{llvm_triple}
+mkdir -pv %{buildroot}%{_prefix}/lib/clang/%{maj_ver}/lib/%{llvm_triple}
+mv %{buildroot}%{_prefix}/lib/clang/%{maj_ver}/lib/powerpc64le-redhat-linux-gnu/* %{buildroot}%{_prefix}/lib/clang/%{maj_ver}/lib/%{llvm_triple}
 %endif

 %ifarch %{ix86}
@ -2141,6 +2344,62 @@ rm -rf %{buildroot}%{install_prefix}/src/python
 %endif
 #endregion mlir installation

+#region flang installation
+%if %{with flang}
+# Remove unnecessary files.
+rm -rfv %{buildroot}%{install_libdir}/cmake/flang
+
+# Remove runtime development headers (see https://github.com/llvm/llvm-project/pull/165610)
+rm -rfv %{buildroot}%{install_includedir}/flang-rt
+
+rm -v %{buildroot}%{install_libdir}/libFIRAnalysis.a \
+      %{buildroot}%{install_libdir}/libFIRBuilder.a \
+      %{buildroot}%{install_libdir}/libFIRCodeGen.a \
+      %{buildroot}%{install_libdir}/libFIRCodeGenDialect.a \
+      %{buildroot}%{install_libdir}/libFIRDialect.a \
+      %{buildroot}%{install_libdir}/libFIRDialectSupport.a \
+      %{buildroot}%{install_libdir}/libFIROpenACCSupport.a \
+      %{buildroot}%{install_libdir}/libFIROpenMPSupport.a \
+      %{buildroot}%{install_libdir}/libFIRSupport.a \
+      %{buildroot}%{install_libdir}/libFIRTestAnalysis.a \
+      %{buildroot}%{install_libdir}/libFIRTestOpenACCInterfaces.a \
+      %{buildroot}%{install_libdir}/libFIRTransforms.a \
+      %{buildroot}%{install_libdir}/libflangFrontend.a \
+      %{buildroot}%{install_libdir}/libflangFrontendTool.a \
+      %{buildroot}%{install_libdir}/libflangPasses.a \
+      %{buildroot}%{install_libdir}/libFlangOpenMPTransforms.a \
+      %{buildroot}%{install_libdir}/libFortranEvaluate.a \
+      %{buildroot}%{install_libdir}/libFortranLower.a \
+      %{buildroot}%{install_libdir}/libFortranParser.a \
+      %{buildroot}%{install_libdir}/libFortranSemantics.a \
+      %{buildroot}%{install_libdir}/libFortranSupport.a \
+      %{buildroot}%{install_libdir}/libHLFIRDialect.a \
+      %{buildroot}%{install_libdir}/libHLFIRTransforms.a \
+      %{buildroot}%{install_libdir}/libCUFAttrs.a \
+      %{buildroot}%{install_libdir}/libCUFDialect.a \
+      %{buildroot}%{install_libdir}/libFortranDecimal.a
+%if %{maj_ver} >= 22
+rm -v %{buildroot}%{install_libdir}/libFortranUtils.a \
+      %{buildroot}%{install_libdir}/libFIROpenACCAnalysis.a \
+      %{buildroot}%{install_libdir}/libFIROpenACCTransforms.a \
+      %{buildroot}%{install_libdir}/libMIFDialect.a
+%endif
+
+find %{buildroot}%{install_includedir}/flang -type f -a ! -iname '*.mod' -delete
+
+# this is a test binary
+rm -v %{buildroot}%{install_bindir}/f18-parse-demo
+
+# Probably this directory already existed before
+mkdir -pv %{buildroot}%{_sysconfdir}/%{pkg_name_clang}/
+echo " %{cfg_file_content_flang}" >> %{buildroot}%{_sysconfdir}/%{pkg_name_clang}/%{_target_platform}-flang.cfg
+%ifarch x86_64
+# On x86_64, install an additional config file.
+echo " %{cfg_file_content_flang}" >> %{buildroot}%{_sysconfdir}/%{pkg_name_clang}/i386-redhat-linux-gnu-flang.cfg
+%endif
+%endif
+#endregion flang installation
+
 #region libcxx installation
 %if %{with libcxx}
 # We can't install the unversionned path on default location because that would conflict with
@ -2195,14 +2454,14 @@ move_and_replace_with_symlinks %{buildroot}%{install_datadir} %{buildroot}%{_dat
 mkdir -p %{buildroot}%{_bindir}
 for f in %{buildroot}%{install_bindir}/*; do
  filename=`basename $f`
-  if [[ "$filename" =~ ^(lit|ld|clang-%{maj_ver})$ ]]; then
+  if [[ "$filename" =~ ^(lit|ld|clang-%{maj_ver}|flang-%{maj_ver})$ ]]; then
    continue
  fi
  %if %{with compat_build}
    ln -s ../../%{install_bindir}/$filename %{buildroot}/%{_bindir}/$filename-%{maj_ver}
  %else
-    # clang-NN is already created by the build system.
-    if [[ "$filename" == "clang" ]]; then
+    # clang-NN and flang-NN are already created by the build system.
+    if [[ "$filename" =~ ^(clang|flang)$ ]]; then
      continue
    fi
    ln -s $filename %{buildroot}/%{_bindir}/$filename-%{maj_ver}
@ -2249,6 +2508,17 @@ install -m 0755 ../llvm-compat-libs/lib/liblldb.so.%{compat_maj_ver}* %{buildroo
 # TODO(kkleine): Instead of deleting test files we should mark them as expected
 # to fail. See https://llvm.org/docs/CommandGuide/lit.html#cmdoption-lit-xfail

+# Tell if the GTS version used by the newly built clang is equal to the
+# expected version.
+function is_gts_equal {
+    local gts_used=$(`pwd`/%{_vpath_builddir}/bin/clang -v 2>&1 | grep "Selected GCC installation" | sed 's|.*/\([0-9]\+\)$|\1|')
+    if [[ -z "%{gts_version}" ]]; then
+      return 0
+    fi
+    test "x$gts_used" = "x%{gts_version}"
+    return $?
+}
+
 # Increase open file limit while running tests.
 if [[ $(ulimit -n) -lt 10000 ]]; then
  ulimit -n 10000
@ -2357,6 +2627,7 @@ export LIT_XFAIL="tools/UpdateTestChecks"
 #region Test CLANG
 reset_test_opts
 export LIT_XFAIL="$LIT_XFAIL;clang/test/CodeGen/profile-filter.c"
+
 %cmake_build --target check-clang
 #endregion Test Clang

@ -2539,10 +2810,26 @@ adjust_lit_filter_out test_list_filter_out
 # to pass. And then we can adapt this number.
 export LIT_OPTS="$LIT_OPTS --max-retries-per-test=4"

+%if %{with flang}
+# Without this we run into a libflang_rt.runtime.so not found error.
+# See https://github.com/llvm/llvm-project/pull/150722 for why this only
+# happens when flang is found.
+export LD_LIBRARY_PATH=%{buildroot}%{_prefix}/lib/clang/%{maj_ver}/lib/%{llvm_triple}
+%endif
+
 %if 0%{?rhel}
 # libomp tests are often very slow on s390x brew builders
 %ifnarch s390x riscv64
-%cmake_build --target check-openmp
+# Rarely, the system clang uses a GCC installation directory that is
+# different from what we'd like to build with.
+# Our newly built clang ends up using that old GCC because of the config
+# files under /etc/clang pointing to the old GCC. We won't be able to run all
+# tests because the installed libatomic cannot be found due to our newly built
+# clang using the wrong GCC directory, e.g. we installed the libatomic from
+# the latest GTS, but the installed GCC is 1 version earlier.
+if is_gts_equal; then
+    %cmake_build --target check-openmp
+fi
 %endif
 %else
 %cmake_build --target check-openmp
@ -2603,6 +2890,12 @@ test_list_filter_out+=("MLIR :: python/execution_engine.py")
 test_list_filter_out+=("MLIR :: python/multithreaded_tests.py")
 %endif

+%if %{with flang}
+# TODO(kkleine): This test needs to be re-enabled. I currently only fails when building with flang.
+# Here's the test failure: https://gist.github.com/kwk/5d551e27a28dfc1b34a09dca781f91df
+test_list_filter_out+=("MLIR :: mlir-pdll-lsp-server/view-output.test")
+%endif
+
 adjust_lit_filter_out test_list_filter_out

 export PYTHONPATH=%{buildroot}/%{python3_sitearch}
@ -2638,6 +2931,8 @@ if ! grep -q atomics /proc/cpuinfo; then
 fi
 %endif

+adjust_lit_filter_out test_list_filter_out
+
 %cmake_build --target check-bolt
 %endif
 #endregion BOLT tests
@ -2649,6 +2944,25 @@ reset_test_opts
 %endif
 #endregion polly tests

+#region flang tests
+%if %{with flang}
+reset_test_opts
+
+# https://github.com/llvm/llvm-project/issues/126051
+test_list_filter_out+=("Flang :: Driver/linker-flags.f90")
+
+# We filter our the location.f90 test for now because with LTO+PGO enabled,
+# We miss the location.f90 entry in the loc_kind_array[ base, inclusion] entry.
+# https://github.com/llvm/llvm-project/issues/156629
+test_list_filter_out+=("Flang :: Lower/location.f90")
+
+adjust_lit_filter_out test_list_filter_out
+
+%cmake_build --target check-flang
+%cmake_build --target check-flang-rt
+
+%endif
+#endregion flang tests

 %endif

@ -3012,6 +3326,11 @@ fi
    llvm-opt-fuzzer
    llvm-test-mustache-spec
 }}
+%if %{maj_ver} >= 22
+%{expand_bins %{expand:
+    llvm-cas
+}}
+%endif
 %{expand_mans %{expand:
    llvm-test-mustache-spec
 }}
@ -3371,6 +3690,12 @@ fi
    libMLIR*.so.%{maj_ver}*
 }}

+%if %{maj_ver} >= 22
+%{expand_libs %{expand:
+    libmlir_apfloat_wrappers.so.%{maj_ver}*
+}}
+%endif
+
 %files -n %{pkg_name_mlir}-static
 %expand_libs libMLIR*.a

@ -3402,12 +3727,69 @@ fi
    libMLIR*.so
 }}

+%if %{maj_ver} >= 22
+%{expand_libs %{expand:
+    libmlir_apfloat_wrappers.so
+}}
+%endif
+
 %files -n python%{python3_pkgversion}-%{pkg_name_mlir}
 %{python3_sitearch}/mlir/
 %endif
 #endregion MLIR files

 #region libcxx files
+
+#region flang files
+%if %{with flang}
+%files -n %{pkg_name_flang}
+%license flang/LICENSE.TXT
+%{expand_mans flang}
+%{expand_bins %{expand:
+    tco
+    bbc
+    fir-opt
+    fir-lsp-server
+    flang
+    flang-new
+}}
+%{install_bindir}/flang-%{maj_ver}
+%{expand_includes %{expand:
+    flang/__cuda_builtins.mod
+    flang/__cuda_device.mod
+    flang/__fortran_builtins.mod
+    flang/__fortran_ieee_exceptions.mod
+    flang/__fortran_type_info.mod
+    flang/__ppc_intrinsics.mod
+    flang/__ppc_types.mod
+    flang/cooperative_groups.mod
+    flang/ieee_arithmetic.mod
+    flang/ieee_exceptions.mod
+    flang/ieee_features.mod
+    flang/iso_c_binding.mod
+    flang/iso_fortran_env.mod
+    flang/mma.mod
+    flang/cudadevice.mod
+    flang/iso_fortran_env_impl.mod
+    flang/omp_lib.mod
+    flang/omp_lib_kinds.mod
+    flang/flang_debug.mod
+}}
+%{_sysconfdir}/%{pkg_name_clang}/%{_target_platform}-flang.cfg
+%ifarch x86_64
+%{_sysconfdir}/%{pkg_name_clang}/i386-redhat-linux-gnu-flang.cfg
+%endif
+
+%{_prefix}/lib/clang/%{maj_ver}/include/ISO_Fortran_binding.h
+
+%files -n %{pkg_name_flang}-runtime
+%{_prefix}/lib/clang/%{maj_ver}/lib/%{llvm_triple}/libflang_rt.runtime.a
+%{_prefix}/lib/clang/%{maj_ver}/lib/%{llvm_triple}/libflang_rt.runtime.so
+%config(noreplace) %{_sysconfdir}/ld.so.conf.d/%{pkg_name_flang}-%{_arch}.conf
+
+%endif
+#region flang files
+
 %if %{with libcxx}

 %files -n %{pkg_name_libcxx}
--- a/4
+++ b/4
@ -1,4 +1,4 @@
-SHA512 (llvm-project-21.1.3.src.tar.xz) = d3058e7c18ada2a6a6192c7e75970406520e0d2ba390dba3b89e99f05959198fd2976d38c200f8e6af37fb569d866b6367bf6e0e249fe4b340dfab74499e5723
-SHA512 (llvm-project-21.1.3.src.tar.xz.sig) = d218a4071451e32a77890dd2e7de7a3b8a310ca85c7e6d90b88d85bad128979cf6866c9d772b880b50da2ec117832e77ba162049478c1deb7b0299cae008151a
+SHA512 (llvm-project-21.1.7.src.tar.xz) = ae30a53ed929df979849f7433bf705bc3d540aa9e12a02a175eb2483d1a56f9ca1203c9b67795f6e84cf2407c28d46d5d5351b290d8735adb5206103fee6f379
+SHA512 (llvm-project-21.1.7.src.tar.xz.sig) = d02b09c77abd537eb24d6d43470f962c80a9ec6ccc03ac0efc950d90dbdec5b94dd6abad18143890ff85cee2bdeb7bcf1dac2a576ffcab8ef053d8526417bdcc
 SHA512 (llvm-project-20.1.8.src.tar.xz) = f330e72e6a1da468569049437cc0ba7a41abb816ccece7367189344f7ebfef730f4788ac7af2bef0aa8a49341c15ab1d31e941ffa782f264d11fe0dc05470773
 SHA512 (llvm-project-20.1.8.src.tar.xz.sig) = d74369bdb4d1b82775161ea53c9c5f3a23ce810f4df5ff617123023f9d8ce720e7d6ecc9e17f8ebd39fd9e7a9de79560abdf2ffe73bcb907a43148d43665d619