https://github.com/mtrofin updated
https://github.com/llvm/llvm-project/pull/154635
>From b46d516642b0256250df08742953f3f78f80c2be Mon Sep 17 00:00:00 2001
From: Mircea Trofin <mtro...@google.com>
Date: Wed, 20 Aug 2025 15:04:49 -0700
Subject: [PATCH] [Local] preserve `MD_prof` in `hoistAllInstructionsInto`
---
llvm/lib/IR/Instruction.cpp | 7 ++++---
llvm/lib/Transforms/Scalar/LICM.cpp | 5 +----
.../Transforms/SimplifyCFG/PhiBlockMerge.ll | 21 ++++++++++++-------
3 files changed, 19 insertions(+), 14 deletions(-)
diff --git a/llvm/lib/IR/Instruction.cpp b/llvm/lib/IR/Instruction.cpp
index 5e87b5ff941ad..c1fafd759b5ab 100644
--- a/llvm/lib/IR/Instruction.cpp
+++ b/llvm/lib/IR/Instruction.cpp
@@ -553,16 +553,17 @@ void Instruction::dropUBImplyingAttrsAndUnknownMetadata(
}
void Instruction::dropUBImplyingAttrsAndMetadata(ArrayRef<unsigned> Keep) {
- // !annotation metadata does not impact semantics.
+ // !annotation and !prof metadata does not impact semantics.
// !range, !nonnull and !align produce poison, so they are safe to speculate.
// !noundef and various AA metadata must be dropped, as it generally produces
// immediate undefined behavior.
static const unsigned KnownIDs[] = {
LLVMContext::MD_annotation, LLVMContext::MD_range,
- LLVMContext::MD_nonnull, LLVMContext::MD_align};
+ LLVMContext::MD_nonnull, LLVMContext::MD_align, LLVMContext::MD_prof};
SmallVector<unsigned> KeepIDs;
KeepIDs.reserve(Keep.size() + std::size(KnownIDs));
- append_range(KeepIDs, KnownIDs);
+ append_range(KeepIDs, (!ProfcheckDisableMetadataFixes ? KnownIDs
+ : drop_end(KnownIDs)));
append_range(KeepIDs, Keep);
dropUBImplyingAttrsAndUnknownMetadata(KeepIDs);
}
diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp
b/llvm/lib/Transforms/Scalar/LICM.cpp
index e157cc9212769..973a8aa0002c2 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -1705,10 +1705,7 @@ static void hoist(Instruction &I, const DominatorTree
*DT, const Loop *CurLoop,
// time in isGuaranteedToExecute if we don't actually have anything to
// drop. It is a compile time optimization, not required for
correctness.
!SafetyInfo->isGuaranteedToExecute(I, DT, CurLoop)) {
- if (ProfcheckDisableMetadataFixes)
- I.dropUBImplyingAttrsAndMetadata();
- else
- I.dropUBImplyingAttrsAndMetadata({LLVMContext::MD_prof});
+ I.dropUBImplyingAttrsAndMetadata();
}
if (isa<PHINode>(I))
diff --git a/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge.ll
b/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge.ll
index 2c5889a981db2..08397b5755a3f 100644
--- a/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge.ll
+++ b/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge.ll
@@ -1,20 +1,21 @@
-; NOTE: Assertions have been autogenerated by update_test_checks.py
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
UTC_ARGS: --check-globals all --version 5
; Test merging of blocks that only have PHI nodes in them
;
; RUN: opt < %s -passes=simplifycfg
-simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
;
define i32 @test(i1 %a, i1 %b) {
-; CHECK-LABEL: @test(
-; CHECK: M:
-; CHECK-NEXT: [[DOT:%.*]] = select i1 %b, i32 0, i32 1
-; CHECK-NEXT: [[W:%.*]] = select i1 %a, i32 2, i32 [[DOT]]
+; CHECK-LABEL: define i32 @test(
+; CHECK-SAME: i1 [[A:%.*]], i1 [[B:%.*]]) {
+; CHECK-NEXT: [[M:.*:]]
+; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[B]], i32 0, i32 1, !prof
[[PROF0:![0-9]+]]
+; CHECK-NEXT: [[W:%.*]] = select i1 [[A]], i32 2, i32 [[SPEC_SELECT]],
!prof [[PROF1:![0-9]+]]
; CHECK-NEXT: [[R:%.*]] = add i32 [[W]], 1
; CHECK-NEXT: ret i32 [[R]]
;
- br i1 %a, label %M, label %O
+ br i1 %a, label %M, label %O, !prof !0
O: ; preds = %0
- br i1 %b, label %N, label %Q
+ br i1 %b, label %N, label %Q, !prof !1
Q: ; preds = %O
br label %N
N: ; preds = %Q, %O
@@ -27,3 +28,9 @@ M: ; preds = %N, %0
ret i32 %R
}
+!0 = !{!"branch_weights", i32 11, i32 7}
+!1 = !{!"branch_weights", i32 3, i32 5}
+;.
+; CHECK: [[PROF0]] = !{!"branch_weights", i32 3, i32 5}
+; CHECK: [[PROF1]] = !{!"branch_weights", i32 11, i32 7}
+;.
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