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[DAG] getFreeze()/getNode() - account for operand depth when calling …
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…isGuaranteedNotToBeUndefOrPoison (PR57554)

Similar to #57402 - we were calling isGuaranteedNotToBeUndefOrPoison on the freeze operand (with Depth = 0), but wasn't accounting for the fact that a later isGuaranteedNotToBeUndefOrPoison assertion will call from the new node (with Depth = 0 as well) - which will then recursively call isGuaranteedNotToBeUndefOrPoison for its operands with Depth = 1

Fixes #57554
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RKSimon committed Sep 5, 2022
1 parent 34f4a9e commit 4e6783f
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Showing 2 changed files with 27 additions and 1 deletion.
3 changes: 2 additions & 1 deletion llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
Expand Up @@ -5235,7 +5235,8 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
break;
case ISD::FREEZE:
assert(VT == Operand.getValueType() && "Unexpected VT!");
if (isGuaranteedNotToBeUndefOrPoison(Operand))
if (isGuaranteedNotToBeUndefOrPoison(Operand, /*PoisonOnly*/ false,
/*Depth*/ 1))
return Operand;
break;
case ISD::TokenFactor:
Expand Down
25 changes: 25 additions & 0 deletions llvm/test/CodeGen/X86/pr57554.ll
@@ -0,0 +1,25 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc < %s -mtriple=x86_64-- | FileCheck %s

@a = external dso_local local_unnamed_addr global i8, align 1

define void @PR57554() {
; CHECK-LABEL: PR57554:
; CHECK: # %bb.0:
; CHECK-NEXT: movb %al, a(%rip)
; CHECK-NEXT: retq
%.fr13 = freeze i8 undef
%i = xor i8 %.fr13, -1
%not = sext i8 %i to i32
%add = add i32 %not, 2147483647
%or = or i32 %add, -1794967296
%or4 = or i32 %or, 0
%not5 = xor i32 %or4, -1
%sub = add nsw i32 0, -1
%add7 = add nsw i32 %sub, %not5
%add7.fr = freeze i32 %add7
%i1 = trunc i32 %add7.fr to i8
%conv10 = select i1 false, i8 0, i8 %i1
store i8 %conv10, ptr @a, align 1
ret void
}

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