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[IPCP] Bail on extractvalue's with more than 1 index. 

The replacement code only looks at the first index of the
extractvalue. If there are additional indices we'll end
up doing a bad replacement.

This only happens if the function returns a nested struct. Not
sure if clang ever generates such code. The original report came
from ispc.

Fixes PR43857

Differential Revision: https://reviews.llvm.org/D69656
This commit is contained in:
Craig Topper 2019-10-31 09:45:03 -07:00
parent fdd0815eac
commit 6773435624
2 changed files with 30 additions and 1 deletions
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2
llvm/lib/Transforms/IPO/IPConstantPropagation.cpp
View File

@ -254,7 +254,7 @@ static bool PropagateConstantReturn(Function &F) {
// Find the index of the retval to replace with // Find the index of the retval to replace with
int index = -1; int index = -1;
if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Ins)) if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Ins))
if (EV->hasIndices()) if (EV->getNumIndices() == 1)
index = *EV->idx_begin(); index = *EV->idx_begin();
// If this use uses a specific return value, and we have a replacement, // If this use uses a specific return value, and we have a replacement,

29
llvm/test/Transforms/IPConstantProp/PR43857.ll Normal file
View File

@ -0,0 +1,29 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -S -ipconstprop | FileCheck %s
%struct.wobble = type { i32 }
%struct.zot = type { %struct.wobble, %struct.wobble, %struct.wobble }
declare dso_local fastcc float @bar(%struct.wobble* noalias, <8 x i32>) unnamed_addr
define %struct.zot @widget(<8 x i32> %arg) local_unnamed_addr {
; CHECK-LABEL: define {{[^@]+}}@widget(
; CHECK-NEXT: bb:
; CHECK-NEXT: ret [[STRUCT_ZOT:%.*]] undef
;
bb:
ret %struct.zot undef
}
define void @baz(<8 x i32> %arg) local_unnamed_addr {
; CHECK-LABEL: define {{[^@]+}}@baz(
; CHECK-NEXT: bb:
; CHECK-NEXT: [[TMP:%.*]] = call [[STRUCT_ZOT:%.*]] @widget(<8 x i32> [[ARG:%.*]])
; CHECK-NEXT: [[TMP1:%.*]] = extractvalue [[STRUCT_ZOT]] %tmp, 0, 0
; CHECK-NEXT: ret void
;
bb:
%tmp = call %struct.zot @widget(<8 x i32> %arg)
%tmp1 = extractvalue %struct.zot %tmp, 0, 0
ret void
}