139ad2dd03
Relates: RHEL-140390 [DEV Task]: Rebase LLVM Toolset to LLVM 22 [rhel-10] Resolves: RHEL-140388 Rebase LLVM Toolset to LLVM 22 [rhel-10]
56 lines
2.2 KiB
Diff
56 lines
2.2 KiB
Diff
From ccf0ee68b86f65a6a4e83756f717faad7c779cb1 Mon Sep 17 00:00:00 2001
|
|
From: Nikita Popov <npopov@redhat.com>
|
|
Date: Wed, 11 Mar 2026 18:03:05 +0100
|
|
Subject: [PATCH] [SystemZ] Limit depth of findCCUse()
|
|
|
|
The recursion here has potentially exponential complexity. Avoid
|
|
this by limiting the depth of recursion.
|
|
|
|
An alternative would be to memoize the results. I went with the
|
|
simpler depth limit on the assumption that we don't particularly
|
|
care about very deep value chains here.
|
|
---
|
|
llvm/lib/Target/SystemZ/SystemZISelLowering.cpp | 13 +++++++++----
|
|
1 file changed, 9 insertions(+), 4 deletions(-)
|
|
|
|
diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
|
|
index 2a9cb903f3921..84d66f88a812d 100644
|
|
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
|
|
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
|
|
@@ -8692,7 +8692,12 @@ SDValue SystemZTargetLowering::combineSETCC(
|
|
return SDValue();
|
|
}
|
|
|
|
-static std::pair<SDValue, int> findCCUse(const SDValue &Val) {
|
|
+static std::pair<SDValue, int> findCCUse(const SDValue &Val,
|
|
+ unsigned Depth = 0) {
|
|
+ // Limit depth of potentially exponential walk.
|
|
+ if (Depth > 5)
|
|
+ return std::make_pair(SDValue(), SystemZ::CCMASK_NONE);
|
|
+
|
|
switch (Val.getOpcode()) {
|
|
default:
|
|
return std::make_pair(SDValue(), SystemZ::CCMASK_NONE);
|
|
@@ -8705,7 +8710,7 @@ static std::pair<SDValue, int> findCCUse(const SDValue &Val) {
|
|
SDValue Op4CCReg = Val.getOperand(4);
|
|
if (Op4CCReg.getOpcode() == SystemZISD::ICMP ||
|
|
Op4CCReg.getOpcode() == SystemZISD::TM) {
|
|
- auto [OpCC, OpCCValid] = findCCUse(Op4CCReg.getOperand(0));
|
|
+ auto [OpCC, OpCCValid] = findCCUse(Op4CCReg.getOperand(0), Depth + 1);
|
|
if (OpCC != SDValue())
|
|
return std::make_pair(OpCC, OpCCValid);
|
|
}
|
|
@@ -8722,10 +8727,10 @@ static std::pair<SDValue, int> findCCUse(const SDValue &Val) {
|
|
case ISD::SHL:
|
|
case ISD::SRA:
|
|
case ISD::SRL:
|
|
- auto [Op0CC, Op0CCValid] = findCCUse(Val.getOperand(0));
|
|
+ auto [Op0CC, Op0CCValid] = findCCUse(Val.getOperand(0), Depth + 1);
|
|
if (Op0CC != SDValue())
|
|
return std::make_pair(Op0CC, Op0CCValid);
|
|
- return findCCUse(Val.getOperand(1));
|
|
+ return findCCUse(Val.getOperand(1), Depth + 1);
|
|
}
|
|
}
|
|
|