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[licm] clone metadata when hoisting conditional branch
1 parent f675483 commit 9bea77f

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4 files changed

+133
-3
lines changed

4 files changed

+133
-3
lines changed

‎llvm/lib/IR/DebugInfoMetadata.cpp

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Original file line numberDiff line numberDiff line change
@@ -42,6 +42,10 @@ LLVM_ABI cl::opt<bool> PickMergedSourceLocations(
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cl::desc("Preserve line and column number when merging locations."));
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} // namespace llvm
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cl::opt<bool> DebugInfoPreferSampleProfiling(
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"dbginfo-prefer-sample-profiling", cl::init(false), cl::Hidden,
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cl::desc("Prefer sample profiling over debugability."));
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uint32_t DIType::getAlignInBits() const {
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return (getTag() == dwarf::DW_TAG_LLVM_ptrauth_type ? 0 : SubclassData32);
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}

‎llvm/lib/IR/Instruction.cpp

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@@ -26,9 +26,18 @@
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#include "llvm/IR/Operator.h"
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#include "llvm/IR/ProfDataUtils.h"
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#include "llvm/IR/Type.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Compiler.h"
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using namespace llvm;
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// FIXME: Flag used for an ablation performance test, Issue #147390. Placing it
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// here because referencing IR should be feasible from anywhere. Will be
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// removed after the ablation test.
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cl::opt<bool> ProfcheckDisableMetadataFixes(
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"profcheck-disable-metadata-fixes", cl::Hidden, cl::init(false),
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cl::desc(
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"Disable metadata propagation fixes discovered through Issue #147390"));
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InsertPosition::InsertPosition(Instruction *InsertBefore)
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: InsertAt(InsertBefore ? InsertBefore->getIterator()
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: InstListType::iterator()) {}

‎llvm/lib/Transforms/Scalar/LICM.cpp

Lines changed: 17 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -218,6 +218,8 @@ using PointersAndHasReadsOutsideSet =
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static SmallVector<PointersAndHasReadsOutsideSet, 0>
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collectPromotionCandidates(MemorySSA *MSSA, AliasAnalysis *AA, Loop *L);
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extern cl::opt<bool> ProfcheckDisableMetadataFixes;
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extern cl::opt<bool> DebugInfoPreferSampleProfiling;
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namespace {
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struct LoopInvariantCodeMotion {
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bool runOnLoop(Loop *L, AAResults *AA, LoopInfo *LI, DominatorTree *DT,
@@ -857,9 +859,21 @@ class ControlFlowHoister {
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}
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// Now finally clone BI.
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ReplaceInstWithInst(
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HoistTarget->getTerminator(),
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BranchInst::Create(HoistTrueDest, HoistFalseDest, BI->getCondition()));
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auto *NewBI =
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BranchInst::Create(HoistTrueDest, HoistFalseDest, BI->getCondition(),
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HoistTarget->getTerminator()->getIterator());
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HoistTarget->getTerminator()->eraseFromParent();
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// Handle "performance-related" metadata. In particular:
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// - md_prof: it should also come from the original branch - since the
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// condition was hoisted, the branch probabilities shouldn't change.
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// - debug info should also be the same as the original branch, **if** the
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// user explicitly indicates that.
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if (!ProfcheckDisableMetadataFixes) {
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if (DebugInfoPreferSampleProfiling)
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NewBI->copyMetadata(*BI, {LLVMContext::MD_prof, LLVMContext::MD_dbg});
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else
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NewBI->copyMetadata(*BI, {LLVMContext::MD_prof});
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}
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++NumClonedBranches;
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assert(CurLoop->getLoopPreheader() &&

‎llvm/test/Transforms/LICM/hoist-phi-metadata.ll

Lines changed: 103 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,103 @@
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals --version 2
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; Test that hoisting conditional branches copies the debug and profiling info
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; metadata from the branch being hoisted.
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; RUN: opt -S -passes=licm -licm-control-flow-hoisting=1 %s -o - | FileCheck %s --check-prefixes=FOR-DEBUG
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; RUN: opt -S -passes=licm -licm-control-flow-hoisting=1 -dbginfo-prefer-sample-profiling %s -o - | FileCheck %s --check-prefixes=FOR-AFDO
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define void @triangle_phi(i32 %x, ptr %p) {
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; FOR-DEBUG-LABEL: define void @triangle_phi
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; FOR-DEBUG-SAME: (i32 [[X:%.*]], ptr [[P:%.*]]) {
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; FOR-DEBUG-NEXT: entry:
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; FOR-DEBUG-NEXT: [[CMP1:%.*]] = icmp sgt i32 [[X]], 0
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; FOR-DEBUG-NEXT: br i1 [[CMP1]], label [[IF_LICM:%.*]], label [[THEN_LICM:%.*]], !prof [[PROF2:![0-9]+]]
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; FOR-DEBUG: if.licm:
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; FOR-DEBUG-NEXT: [[ADD:%.*]] = add i32 [[X]], 1
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; FOR-DEBUG-NEXT: br label [[THEN_LICM]]
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; FOR-DEBUG: then.licm:
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; FOR-DEBUG-NEXT: [[PHI:%.*]] = phi i32 [ [[ADD]], [[IF_LICM]] ], [ [[X]], [[ENTRY:%.*]] ]
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; FOR-DEBUG-NEXT: store i32 [[PHI]], ptr [[P]], align 4
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; FOR-DEBUG-NEXT: [[CMP2:%.*]] = icmp ne i32 [[PHI]], 0
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; FOR-DEBUG-NEXT: br label [[LOOP:%.*]]
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; FOR-DEBUG: loop:
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; FOR-DEBUG-NEXT: br i1 [[CMP1]], label [[IF:%.*]], label [[THEN:%.*]], !dbg [[DBG3:![0-9]+]], !prof [[PROF2]]
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; FOR-DEBUG: if:
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; FOR-DEBUG-NEXT: br label [[THEN]]
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; FOR-DEBUG: then:
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; FOR-DEBUG-NEXT: br i1 [[CMP2]], label [[LOOP]], label [[END:%.*]], !dbg [[DBG7:![0-9]+]], !prof [[PROF8:![0-9]+]]
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; FOR-DEBUG: end:
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; FOR-DEBUG-NEXT: ret void
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;
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; FOR-AFDO-LABEL: define void @triangle_phi
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; FOR-AFDO-SAME: (i32 [[X:%.*]], ptr [[P:%.*]]) {
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; FOR-AFDO-NEXT: entry:
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; FOR-AFDO-NEXT: [[CMP1:%.*]] = icmp sgt i32 [[X]], 0
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; FOR-AFDO-NEXT: br i1 [[CMP1]], label [[IF_LICM:%.*]], label [[THEN_LICM:%.*]], !dbg [[DBG2:![0-9]+]], !prof [[PROF6:![0-9]+]]
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; FOR-AFDO: if.licm:
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; FOR-AFDO-NEXT: [[ADD:%.*]] = add i32 [[X]], 1
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; FOR-AFDO-NEXT: br label [[THEN_LICM]]
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; FOR-AFDO: then.licm:
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; FOR-AFDO-NEXT: [[PHI:%.*]] = phi i32 [ [[ADD]], [[IF_LICM]] ], [ [[X]], [[ENTRY:%.*]] ]
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; FOR-AFDO-NEXT: store i32 [[PHI]], ptr [[P]], align 4
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; FOR-AFDO-NEXT: [[CMP2:%.*]] = icmp ne i32 [[PHI]], 0
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; FOR-AFDO-NEXT: br label [[LOOP:%.*]]
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; FOR-AFDO: loop:
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; FOR-AFDO-NEXT: br i1 [[CMP1]], label [[IF:%.*]], label [[THEN:%.*]], !dbg [[DBG2]], !prof [[PROF6]]
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; FOR-AFDO: if:
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; FOR-AFDO-NEXT: br label [[THEN]]
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; FOR-AFDO: then:
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; FOR-AFDO-NEXT: br i1 [[CMP2]], label [[LOOP]], label [[END:%.*]], !dbg [[DBG7:![0-9]+]], !prof [[PROF8:![0-9]+]]
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; FOR-AFDO: end:
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; FOR-AFDO-NEXT: ret void
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;
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entry:
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br label %loop, !dbg !5
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loop:
55+
%cmp1 = icmp sgt i32 %x, 0
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br i1 %cmp1, label %if, label %then, !dbg !6, !prof !8
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if:
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%add = add i32 %x, 1
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br label %then
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then:
62+
%phi = phi i32 [ %add, %if ], [ %x, %loop ]
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store i32 %phi, ptr %p
64+
%cmp2 = icmp ne i32 %phi, 0
65+
br i1 %cmp2, label %loop, label %end, !dbg !7, !prof !9
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67+
end:
68+
ret void
69+
}
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!llvm.module.flags = !{!2, !3}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1)
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!1 = !DIFile(filename: "t", directory: "/")
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!2 = !{i32 7, !"Dwarf Version", i32 5}
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!3 = !{i32 2, !"Debug Info Version", i32 3}
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!4 = distinct !DISubprogram(name: "triangle_phi", linkageName: "triangle_phi", scope: !1, file: !1, line: 1, unit: !0)
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!5 = !DILocation(line: 1, column: 22, scope: !4)
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!6 = !DILocation(line: 2, column: 22, scope: !4)
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!7 = !DILocation(line: 3, column: 22, scope: !4)
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!8 = !{!"branch_weights", i32 5, i32 7}
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!9 = !{!"branch_weights", i32 13, i32 11}
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;.
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; FOR-DEBUG: [[META0:![0-9]+]] = !{i32 7, !"Dwarf Version", i32 5}
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; FOR-DEBUG: [[META1:![0-9]+]] = !{i32 2, !"Debug Info Version", i32 3}
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; FOR-DEBUG: [[PROF2]] = !{!"branch_weights", i32 5, i32 7}
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; FOR-DEBUG: [[DBG3]] = !DILocation(line: 2, column: 22, scope: [[META4:![0-9]+]])
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; FOR-DEBUG: [[META4]] = distinct !DISubprogram(name: "triangle_phi", linkageName: "triangle_phi", scope: [[META5:![0-9]+]], file: [[META5]], line: 1, spFlags: DISPFlagDefinition, unit: [[META6:![0-9]+]])
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; FOR-DEBUG: [[META5]] = !DIFile(filename: "{{.*}}t", directory: {{.*}})
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; FOR-DEBUG: [[META6]] = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: [[META5]], isOptimized: false, runtimeVersion: 0, emissionKind: NoDebug)
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; FOR-DEBUG: [[DBG7]] = !DILocation(line: 3, column: 22, scope: [[META4]])
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; FOR-DEBUG: [[PROF8]] = !{!"branch_weights", i32 13, i32 11}
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;.
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; FOR-AFDO: [[META0:![0-9]+]] = !{i32 7, !"Dwarf Version", i32 5}
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; FOR-AFDO: [[META1:![0-9]+]] = !{i32 2, !"Debug Info Version", i32 3}
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; FOR-AFDO: [[DBG2]] = !DILocation(line: 2, column: 22, scope: [[META3:![0-9]+]])
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; FOR-AFDO: [[META3]] = distinct !DISubprogram(name: "triangle_phi", linkageName: "triangle_phi", scope: [[META4:![0-9]+]], file: [[META4]], line: 1, spFlags: DISPFlagDefinition, unit: [[META5:![0-9]+]])
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; FOR-AFDO: [[META4]] = !DIFile(filename: "{{.*}}t", directory: {{.*}})
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; FOR-AFDO: [[META5]] = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: [[META4]], isOptimized: false, runtimeVersion: 0, emissionKind: NoDebug)
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; FOR-AFDO: [[PROF6]] = !{!"branch_weights", i32 5, i32 7}
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; FOR-AFDO: [[DBG7]] = !DILocation(line: 3, column: 22, scope: [[META3]])
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; FOR-AFDO: [[PROF8]] = !{!"branch_weights", i32 13, i32 11}
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;.

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