Use the ieee128 format for long double on ppc64le

gcc switched to ieee128 as the default in Fedora >=36, so clang needs to do
this to maintain ABI compatibility.

clang.spec

@@ -41,7 +41,7 @@
 
 Name:		%pkg_name
 Version:	%{clang_version}%{?rc_ver:~rc%{rc_ver}}
-Release:	2%{?dist}
+Release:	3%{?dist}
 Summary:	A C language family front-end for LLVM
 
 License:	NCSA
@@ -316,6 +316,7 @@ CFLAGS="$CFLAGS -Wno-address -Wno-nonnull -Wno-maybe-uninitialized"
 
 # -DLLVM_ENABLE_NEW_PASS_MANAGER=ON can be removed once this patch is committed:
 # https://reviews.llvm.org/D107628
+# -DPPC_LINUX_DEFAULT_IEEELONGDOUBLE=ON to match gcc.
 %cmake  -G Ninja \
 	-DLLVM_PARALLEL_LINK_JOBS=1 \
 	-DLLVM_LINK_LLVM_DYLIB:BOOL=ON \
@@ -365,6 +366,9 @@ CFLAGS="$CFLAGS -Wno-address -Wno-nonnull -Wno-maybe-uninitialized"
 	-DCLANG_BUILD_EXAMPLES:BOOL=OFF \
 	-DBUILD_SHARED_LIBS=OFF \
 	-DCLANG_REPOSITORY_STRING="%{?fedora:Fedora}%{?rhel:Red Hat} %{version}-%{release}" \
+%if 0%{?fedora}
+	-DPPC_LINUX_DEFAULT_IEEELONGDOUBLE=ON \
+%endif
 %ifarch %{arm}
 	-DCLANG_DEFAULT_LINKER=lld \
 %endif
@@ -597,6 +601,9 @@ false
 
 %endif
 %changelog
+* Thu May 19 2022 Tom Stellard <tstellar@redhat.com> - 14.0.0-3
+- Use the ieee128 format for long double on ppc64le
+
 * Mon Apr 04 2022 Jeremy Newton <alexjnewt AT hotmail DOT com> - 14.0.0-2
 - Add patch for HIP (cherry-picked from llvm trunk, to be LLVM15)
 

tests/ppc64le-long-double/main.fmf

@@ -0,0 +1,7 @@
+summary: Test that gcc and clang use the same long double format on ppc64le
+require:
+  - clang
+  - qemu-user-static
+  - mock
+test: ./runtest.sh
+duration: 1h

tests/ppc64le-long-double/runtest.sh

@@ -0,0 +1,14 @@
+set -e
+
+fedora_release=`rpm -E %{fedora}`
+mock_root=fedora-$fedora_release-ppc64le
+triple=ppc64le-redhat-linux
+
+mock -r $mock_root --isolation=simple --install gcc
+gcc_output=$(mock -r $mock_root --isolation=simple -q --shell gcc -E -dM -x c /dev/null | grep -e __LONG_DOUBLE_IEEE128__ -e __LONG_DOUBLE_IBM128__)
+clang_output=$(clang -target $triple  -E -dM -x c /dev/null | grep -e __LONG_DOUBLE_IEEE128__ -e __LONG_DOUBLE_IBM128__)
+
+echo "gcc:   $gcc_output"
+echo "clang: $clang_output"
+
+test "$gcc_output" = "$clang_output"