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[InlineCost] Simplify extractvalue across callsite #145054

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[InlineCost] Simplify extractvalue across callsite #145054

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[InlineCost] Simplify extractvalue across callsite
tobias-stadler Jun 18, 2025
0767ab9
Add negative test
tobias-stadler Jun 23, 2025
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15 changes: 12 additions & 3 deletions llvm/lib/Analysis/InlineCost.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2316,9 +2316,18 @@ bool CallAnalyzer::visitStore(StoreInst &I) {
}

bool CallAnalyzer::visitExtractValue(ExtractValueInst &I) {
// Constant folding for extract value is trivial.
if (simplifyInstruction(I))
return true;
Value *Op = I.getAggregateOperand();

// Special handling, because we want to simplify extractvalue with a
// potential insertvalue from the caller.
if (Value *SimpleOp = getSimplifiedValueUnchecked(Op)) {
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It would be good to split off the change from constant -> constant and then improve extract value handling in a separate pqtch

SimplifyQuery SQ(DL);
Value *SimpleV = simplifyExtractValueInst(SimpleOp, I.getIndices(), SQ);
if (SimpleV) {
SimplifiedValues[&I] = SimpleV;
return true;
}
}

// SROA can't look through these, but they may be free.
return Base::visitExtractValue(I);
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53 changes: 53 additions & 0 deletions llvm/test/Transforms/Inline/simplify-crosscallsite.ll
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This test also passes without your change. You could use a recursive call to prove that the recursive code path is eliminated. Alternative could check debug output.

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@tobias-stadler tobias-stadler Jun 23, 2025 •
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Oops, x86 has lower cost than AArch64 here. Thanks!

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Could you please also add a negative test where extractvalue does not simplify (e.g. same as current but swap 0 and 1).

Original file line number Diff line number Diff line change
@@ -0,0 +1,53 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt < %s -S -passes=inline | FileCheck %s

define i32 @callee([2 x i32] %agg) {
; CHECK-LABEL: define i32 @callee(
; CHECK-SAME: [2 x i32] [[AGG:%.*]]) {
; CHECK-NEXT: [[V:%.*]] = extractvalue [2 x i32] [[AGG]], 0
; CHECK-NEXT: [[C:%.*]] = icmp eq i32 [[V]], 0
; CHECK-NEXT: br i1 [[C]], label %[[IS_NULL:.*]], label %[[NON_NULL:.*]]
; CHECK: [[IS_NULL]]:
; CHECK-NEXT: ret i32 0
; CHECK: [[NON_NULL]]:
; CHECK-NEXT: [[R:%.*]] = call i32 @callee([2 x i32] [[AGG]])
; CHECK-NEXT: ret i32 [[R]]
;
%v = extractvalue [2 x i32] %agg, 0
%c = icmp eq i32 %v, 0
br i1 %c, label %is_null, label %non_null

is_null:
ret i32 0

non_null:
%r = call i32 @callee([2 x i32] %agg)
ret i32 %r
}

define i32 @caller_simplified(i32 %arg) {
; CHECK-LABEL: define i32 @caller_simplified(
; CHECK-SAME: i32 [[ARG:%.*]]) {
; CHECK-NEXT: [[AGG0:%.*]] = insertvalue [2 x i32] poison, i32 0, 0
; CHECK-NEXT: [[AGG1:%.*]] = insertvalue [2 x i32] [[AGG0]], i32 [[ARG]], 1
; CHECK-NEXT: ret i32 0
;
%agg0 = insertvalue [2 x i32] poison, i32 0, 0
%agg1 = insertvalue [2 x i32] %agg0, i32 %arg, 1
%v = call i32 @callee([2 x i32] %agg1)
ret i32 %v
}

define i32 @caller_not_simplified(i32 %arg) {
; CHECK-LABEL: define i32 @caller_not_simplified(
; CHECK-SAME: i32 [[ARG:%.*]]) {
; CHECK-NEXT: [[AGG0:%.*]] = insertvalue [2 x i32] poison, i32 1, 0
; CHECK-NEXT: [[AGG1:%.*]] = insertvalue [2 x i32] [[AGG0]], i32 [[ARG]], 1
; CHECK-NEXT: [[V:%.*]] = call i32 @callee([2 x i32] [[AGG1]])
; CHECK-NEXT: ret i32 [[V]]
;
%agg0 = insertvalue [2 x i32] poison, i32 1, 0
%agg1 = insertvalue [2 x i32] %agg0, i32 %arg, 1
%v = call i32 @callee([2 x i32] %agg1)
ret i32 %v
}
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