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release/20.x: [CodeGenPrepare] Replace deleted ext instr with the promoted value. (#71058) #125040

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Merged
merged 1 commit into from
Feb 1, 2025
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release/20.x: [CodeGenPrepare] Replace deleted ext instr with the promoted value. (#71058) #125040

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11 changes: 11 additions & 0 deletions llvm/lib/CodeGen/CodeGenPrepare.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3074,6 +3074,14 @@ struct ExtAddrMode : public TargetLowering::AddrMode {
void print(raw_ostream &OS) const;
void dump() const;

// Replace From in ExtAddrMode with To.
// E.g., SExt insts may be promoted and deleted. We should replace them with
// the promoted values.
void replaceWith(Value *From, Value *To) {
if (ScaledReg == From)
ScaledReg = To;
}

FieldName compare(const ExtAddrMode &other) {
// First check that the types are the same on each field, as differing types
// is something we can't cope with later on.
Expand Down Expand Up @@ -5365,6 +5373,9 @@ bool AddressingModeMatcher::matchOperationAddr(User *AddrInst, unsigned Opcode,
TPT.rollback(LastKnownGood);
return false;
}

// SExt has been deleted. Make sure it is not referenced by the AddrMode.
AddrMode.replaceWith(Ext, PromotedOperand);
return true;
}
case Instruction::Call:
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48 changes: 48 additions & 0 deletions llvm/test/CodeGen/X86/codegen-prepare-addrmode-sext.ll
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Expand Up @@ -620,3 +620,51 @@ define i8 @oneArgPromotionBlockSExtZExt(i1 %arg1, ptr %base) {
%res = load i8, ptr %arrayidx
ret i8 %res
}

; Check that we replace the deleted sext with the promoted value.
define void @pr70938(ptr %f) {
; CHECK-LABEL: define void @pr70938(
; CHECK-SAME: ptr [[F:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[ADD:%.*]] = add nsw i64 0, 1
; CHECK-NEXT: [[SUNKADDR:%.*]] = mul i64 [[ADD]], 2
; CHECK-NEXT: [[SUNKADDR1:%.*]] = getelementptr i8, ptr [[F]], i64 [[SUNKADDR]]
; CHECK-NEXT: [[SUNKADDR2:%.*]] = getelementptr i8, ptr [[SUNKADDR1]], i64 1
; CHECK-NEXT: store i8 0, ptr [[SUNKADDR2]], align 1
; CHECK-NEXT: ret void
;
entry:
%add = add nsw i32 0, 1
%idxprom3 = sext i32 %add to i64
%arrayidx4 = getelementptr [2 x [1 x [2 x i8]]], ptr %f, i64 0, i64 %idxprom3
%arrayidx8 = getelementptr [2 x i8], ptr %arrayidx4, i64 0, i64 %idxprom3
br label %if.end

if.end: ; preds = %entry
store i8 0, ptr %arrayidx8, align 1
ret void
}

define void @pr119429() {
; CHECK-LABEL: define void @pr119429() {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[AND:%.*]] = and i64 0, 0
; CHECK-NEXT: [[SUNKADDR:%.*]] = inttoptr i64 [[AND]] to ptr
; CHECK-NEXT: [[SUNKADDR1:%.*]] = mul i64 [[AND]], 2
; CHECK-NEXT: [[SUNKADDR2:%.*]] = getelementptr i8, ptr [[SUNKADDR]], i64 [[SUNKADDR1]]
; CHECK-NEXT: store i64 0, ptr [[SUNKADDR2]], align 8
; CHECK-NEXT: ret void
;
entry:
%and = and i32 0, 0
%conv1 = zext i32 %and to i64
%sub = add i64 %conv1, 0
br label %if.end

if.end:
%mul = shl i64 %sub, 1
%add = add i64 %mul, %conv1
%ptr = inttoptr i64 %add to ptr
store i64 0, ptr %ptr, align 8
ret void
}
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