[llvm] [CHR] Make Selects Created in MergedCondition have Unknown Profdata (PR #167534)

via llvm-commits llvm-commits at lists.llvm.org
Tue Nov 11 08:55:33 PST 2025 

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Aiden Grossman (boomanaiden154)

<details>
<summary>Changes</summary>

These selects are dependent on values live into the CHRScope that we cannot infer anything about, so mark the branch weights unknown. These selects usually also just get folded down into a icmps, so the profile informatio ends up being kind of redundant.

---
Full diff: https://github.com/llvm/llvm-project/pull/167534.diff


3 Files Affected:

- (modified) llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp (+2) 
- (modified) llvm/test/Transforms/PGOProfile/chr-lifetimes.ll (+45-22) 
- (modified) llvm/utils/profcheck-xfail.txt (-4) 


``````````diff
diff --git a/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp b/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
index 0688bc7ac08eb..726d94b27a7f2 100644
--- a/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
+++ b/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
@@ -1992,6 +1992,8 @@ void CHR::addToMergedCondition(bool IsTrueBiased, Value *Cond,
 
   // Use logical and to avoid propagating poison from later conditions.
   MergedCondition = IRB.CreateLogicalAnd(MergedCondition, Cond);
+  setExplicitlyUnknownBranchWeightsIfProfiled(
+      *cast<Instruction>(MergedCondition), DEBUG_TYPE);
 }
 
 void CHR::transformScopes(SmallVectorImpl<CHRScope *> &CHRScopes) {
diff --git a/llvm/test/Transforms/PGOProfile/chr-lifetimes.ll b/llvm/test/Transforms/PGOProfile/chr-lifetimes.ll
index b29834f9fe960..8505a3f4f158f 100644
--- a/llvm/test/Transforms/PGOProfile/chr-lifetimes.ll
+++ b/llvm/test/Transforms/PGOProfile/chr-lifetimes.ll
@@ -1,4 +1,4 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals
 ; RUN: opt < %s -passes='require<profile-summary>,chr' -S | FileCheck %s
 
 declare void @foo()
@@ -14,21 +14,21 @@ define void @test_chr_with_lifetimes(ptr %i) !prof !14 {
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i32, ptr [[I:%.*]], align 4
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp ne i32 [[TMP0]], 0
 ; CHECK-NEXT:    [[TMP9:%.*]] = freeze i1 [[TMP1]]
-; CHECK-NEXT:    [[TMP10:%.*]] = select i1 true, i1 [[TMP9]], i1 false
+; CHECK-NEXT:    [[TMP8:%.*]] = select i1 true, i1 [[TMP9]], i1 false, !prof [[PROF15:![0-9]+]]
 ; CHECK-NEXT:    [[TMP11:%.*]] = freeze i1 [[TMP1]]
-; CHECK-NEXT:    [[TMP5:%.*]] = select i1 [[TMP10]], i1 [[TMP11]], i1 false
-; CHECK-NEXT:    br i1 [[TMP5]], label [[ENTRY_SPLIT:%.*]], label [[ENTRY_SPLIT_NONCHR:%.*]], !prof [[PROF15:![0-9]+]]
+; CHECK-NEXT:    [[TMP5:%.*]] = select i1 [[TMP8]], i1 [[TMP11]], i1 false, !prof [[PROF15]]
+; CHECK-NEXT:    br i1 [[TMP5]], label [[ENTRY_SPLIT:%.*]], label [[ENTRY_SPLIT_NONCHR:%.*]], !prof [[PROF16:![0-9]+]]
 ; CHECK:       entry.split:
-; CHECK-NEXT:    [[TMP6:%.*]] = select i1 true, i64 0, i64 4, !prof [[PROF16:![0-9]+]]
+; CHECK-NEXT:    [[TMP6:%.*]] = select i1 true, i64 0, i64 4, !prof [[PROF17:![0-9]+]]
 ; CHECK-NEXT:    call void @baz(i64 [[TMP6]])
-; CHECK-NEXT:    br i1 false, label [[BB1:%.*]], label [[BB0:%.*]], !prof [[PROF17:![0-9]+]]
+; CHECK-NEXT:    br i1 false, label [[BB1:%.*]], label [[BB0:%.*]], !prof [[PROF18:![0-9]+]]
 ; CHECK:       bb0:
 ; CHECK-NEXT:    call void @foo()
 ; CHECK-NEXT:    br label [[BB1]]
 ; CHECK:       entry.split.nonchr:
-; CHECK-NEXT:    [[TMP7:%.*]] = select i1 [[TMP1]], i64 0, i64 4, !prof [[PROF16]]
+; CHECK-NEXT:    [[TMP7:%.*]] = select i1 [[TMP1]], i64 0, i64 4, !prof [[PROF17]]
 ; CHECK-NEXT:    call void @baz(i64 [[TMP7]])
-; CHECK-NEXT:    br i1 [[TMP1]], label [[BB0_NONCHR:%.*]], label [[BB1]], !prof [[PROF16]]
+; CHECK-NEXT:    br i1 [[TMP1]], label [[BB0_NONCHR:%.*]], label [[BB1]], !prof [[PROF17]]
 ; CHECK:       bb0.nonchr:
 ; CHECK-NEXT:    call void @foo()
 ; CHECK-NEXT:    br label [[BB1]]
@@ -83,24 +83,24 @@ define void @test_chr_dynamic_alloca(ptr %i) !prof !14 {
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i32, ptr [[I]], align 4
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp ne i32 [[TMP0]], 0
 ; CHECK-NEXT:    [[TMP2:%.*]] = freeze i1 [[TMP1]]
-; CHECK-NEXT:    [[TMP3:%.*]] = select i1 true, i1 [[TMP2]], i1 false
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 true, i1 [[TMP2]], i1 false, !prof [[PROF15]]
 ; CHECK-NEXT:    [[TMP4:%.*]] = freeze i1 [[TMP1]]
-; CHECK-NEXT:    [[TMP5:%.*]] = select i1 [[TMP3]], i1 [[TMP4]], i1 false
-; CHECK-NEXT:    br i1 [[TMP5]], label [[BB4_SPLIT:%.*]], label [[BB4_SPLIT_NONCHR:%.*]], !prof [[PROF15]]
+; CHECK-NEXT:    [[TMP5:%.*]] = select i1 [[TMP3]], i1 [[TMP4]], i1 false, !prof [[PROF15]]
+; CHECK-NEXT:    br i1 [[TMP5]], label [[BB4_SPLIT:%.*]], label [[BB4_SPLIT_NONCHR:%.*]], !prof [[PROF16]]
 ; CHECK:       bb4.split:
-; CHECK-NEXT:    [[TMP6:%.*]] = select i1 true, i64 0, i64 4, !prof [[PROF16]]
+; CHECK-NEXT:    [[TMP6:%.*]] = select i1 true, i64 0, i64 4, !prof [[PROF17]]
 ; CHECK-NEXT:    [[TEST:%.*]] = alloca i32, align 8
 ; CHECK-NEXT:    call void @baz(i64 [[TMP6]])
-; CHECK-NEXT:    br i1 false, label [[BB1:%.*]], label [[BB0:%.*]], !prof [[PROF17]]
+; CHECK-NEXT:    br i1 false, label [[BB1:%.*]], label [[BB0:%.*]], !prof [[PROF18]]
 ; CHECK:       bb0:
 ; CHECK-NEXT:    call void @foo()
 ; CHECK-NEXT:    store ptr [[TEST]], ptr [[I]], align 8
 ; CHECK-NEXT:    br label [[BB1]]
 ; CHECK:       bb4.split.nonchr:
-; CHECK-NEXT:    [[TMP7:%.*]] = select i1 [[TMP1]], i64 0, i64 4, !prof [[PROF16]]
+; CHECK-NEXT:    [[TMP7:%.*]] = select i1 [[TMP1]], i64 0, i64 4, !prof [[PROF17]]
 ; CHECK-NEXT:    [[TEST_NONCHR:%.*]] = alloca i32, align 8
 ; CHECK-NEXT:    call void @baz(i64 [[TMP7]])
-; CHECK-NEXT:    br i1 [[TMP1]], label [[BB0_NONCHR:%.*]], label [[BB1]], !prof [[PROF16]]
+; CHECK-NEXT:    br i1 [[TMP1]], label [[BB0_NONCHR:%.*]], label [[BB1]], !prof [[PROF17]]
 ; CHECK:       bb0.nonchr:
 ; CHECK-NEXT:    call void @foo()
 ; CHECK-NEXT:    store ptr [[TEST_NONCHR]], ptr [[I]], align 8
@@ -167,21 +167,21 @@ define void @test_no_move_allocas(ptr %i) !prof !14 {
 ; CHECK-NEXT:    [[TMP0:%.*]] = load i32, ptr [[I:%.*]], align 4
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp ne i32 [[TMP0]], 0
 ; CHECK-NEXT:    [[TMP2:%.*]] = freeze i1 [[TMP1]]
-; CHECK-NEXT:    [[TMP3:%.*]] = select i1 true, i1 [[TMP2]], i1 false
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 true, i1 [[TMP2]], i1 false, !prof [[PROF15]]
 ; CHECK-NEXT:    [[TMP4:%.*]] = freeze i1 [[TMP1]]
-; CHECK-NEXT:    [[TMP5:%.*]] = select i1 [[TMP3]], i1 [[TMP4]], i1 false
-; CHECK-NEXT:    br i1 [[TMP5]], label [[ENTRY_SPLIT:%.*]], label [[ENTRY_SPLIT_NONCHR:%.*]], !prof [[PROF15]]
+; CHECK-NEXT:    [[TMP5:%.*]] = select i1 [[TMP3]], i1 [[TMP4]], i1 false, !prof [[PROF15]]
+; CHECK-NEXT:    br i1 [[TMP5]], label [[ENTRY_SPLIT:%.*]], label [[ENTRY_SPLIT_NONCHR:%.*]], !prof [[PROF16]]
 ; CHECK:       entry.split:
-; CHECK-NEXT:    [[TMP6:%.*]] = select i1 true, i64 0, i64 4, !prof [[PROF16]]
+; CHECK-NEXT:    [[TMP6:%.*]] = select i1 true, i64 0, i64 4, !prof [[PROF17]]
 ; CHECK-NEXT:    call void @baz(i64 [[TMP6]])
-; CHECK-NEXT:    br i1 false, label [[BB1:%.*]], label [[BB0:%.*]], !prof [[PROF17]]
+; CHECK-NEXT:    br i1 false, label [[BB1:%.*]], label [[BB0:%.*]], !prof [[PROF18]]
 ; CHECK:       bb0:
 ; CHECK-NEXT:    call void @foo()
 ; CHECK-NEXT:    br label [[BB1]]
 ; CHECK:       entry.split.nonchr:
-; CHECK-NEXT:    [[TMP7:%.*]] = select i1 [[TMP1]], i64 0, i64 4, !prof [[PROF16]]
+; CHECK-NEXT:    [[TMP7:%.*]] = select i1 [[TMP1]], i64 0, i64 4, !prof [[PROF17]]
 ; CHECK-NEXT:    call void @baz(i64 [[TMP7]])
-; CHECK-NEXT:    br i1 [[TMP1]], label [[BB0_NONCHR:%.*]], label [[BB1]], !prof [[PROF16]]
+; CHECK-NEXT:    br i1 [[TMP1]], label [[BB0_NONCHR:%.*]], label [[BB1]], !prof [[PROF17]]
 ; CHECK:       bb0.nonchr:
 ; CHECK-NEXT:    call void @foo()
 ; CHECK-NEXT:    br label [[BB1]]
@@ -243,3 +243,26 @@ bb3:
 !14 = !{!"function_entry_count", i64 100}
 !15 = !{!"branch_weights", i32 0, i32 1}
 ; CHECK: !15 = !{!"branch_weights", i32 1000, i32 0}
+;.
+; CHECK: attributes #[[ATTR0:[0-9]+]] = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+;.
+; CHECK: [[META0:![0-9]+]] = !{i32 1, !"ProfileSummary", [[META1:![0-9]+]]}
+; CHECK: [[META1]] = !{[[META2:![0-9]+]], [[META3:![0-9]+]], [[META4:![0-9]+]], [[META5:![0-9]+]], [[META6:![0-9]+]], [[META7:![0-9]+]], [[META8:![0-9]+]], [[META9:![0-9]+]]}
+; CHECK: [[META2]] = !{!"ProfileFormat", !"InstrProf"}
+; CHECK: [[META3]] = !{!"TotalCount", i64 10000}
+; CHECK: [[META4]] = !{!"MaxCount", i64 10}
+; CHECK: [[META5]] = !{!"MaxInternalCount", i64 1}
+; CHECK: [[META6]] = !{!"MaxFunctionCount", i64 1000}
+; CHECK: [[META7]] = !{!"NumCounts", i64 3}
+; CHECK: [[META8]] = !{!"NumFunctions", i64 3}
+; CHECK: [[META9]] = !{!"DetailedSummary", [[META10:![0-9]+]]}
+; CHECK: [[META10]] = !{[[META11:![0-9]+]], [[META12:![0-9]+]], [[META13:![0-9]+]]}
+; CHECK: [[META11]] = !{i32 10000, i64 100, i32 1}
+; CHECK: [[META12]] = !{i32 999000, i64 100, i32 1}
+; CHECK: [[META13]] = !{i32 999999, i64 1, i32 2}
+; CHECK: [[META14:![0-9]+]] = !{!"function_entry_count", i64 100}
+; CHECK: [[PROF15]] = !{!"unknown", !"chr"}
+; CHECK: [[PROF16]] = !{!"branch_weights", i32 1000, i32 0}
+; CHECK: [[PROF17]] = !{!"branch_weights", i32 1, i32 0}
+; CHECK: [[PROF18]] = !{!"branch_weights", i32 0, i32 1}
+;.
diff --git a/llvm/utils/profcheck-xfail.txt b/llvm/utils/profcheck-xfail.txt
index b1f20a73c3b2b..e1e76f594895a 100644
--- a/llvm/utils/profcheck-xfail.txt
+++ b/llvm/utils/profcheck-xfail.txt
@@ -608,10 +608,6 @@ Transforms/OpenMP/spmdization.ll
 Transforms/OpenMP/spmdization_no_guarding_two_reaching_kernels.ll
 Transforms/OpenMP/spmdization_remarks.ll
 Transforms/PartiallyInlineLibCalls/X86/good-prototype.ll
-Transforms/PGOProfile/chr-dead-pred.ll
-Transforms/PGOProfile/chr-dup-threshold.ll
-Transforms/PGOProfile/chr-lifetimes.ll
-Transforms/PGOProfile/chr-poison.ll
 Transforms/PGOProfile/comdat.ll
 Transforms/PGOProfile/memop_profile_funclet_wasm.ll
 Transforms/PGOProfile/profcheck-select.ll

``````````

</details>


https://github.com/llvm/llvm-project/pull/167534

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