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[CodeGenPrepare][AddressingModeMatcher] Fix a think-o for the sext(zext) -> zext promotion

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introduced in r217629.
We were returning the old sext instead of the new zext as the promoted instruction!

Thanks Joerg Sonnenberger for the test case.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217800 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Quentin Colombet 2014-09-15 18:26:58 +00:00
parent 348e9e7b6d
commit 49e423ca30
2 changed files with 72 additions and 7 deletions
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16
lib/CodeGen/CodeGenPrepare.cpp
View File

@ -1849,6 +1849,7 @@ Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
// By construction, the operand of SExt is an instruction. Otherwise we cannot
// get through it and this method should not be called.
Instruction *SExtOpnd = cast<Instruction>(SExt->getOperand(0));
Instruction *ExtInst = SExt;
if (isa<ZExtInst>(SExtOpnd)) {
// Replace sext(zext(opnd))
// => zext(opnd).
@ -1856,6 +1857,7 @@ Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
TPT.createZExt(SExt, SExtOpnd->getOperand(0), SExt->getType());
TPT.replaceAllUsesWith(SExt, ZExt);
TPT.eraseInstruction(SExt);
ExtInst = ZExt;
} else {
// Replace sext(trunc(opnd)) or sext(sext(opnd))
// => sext(opnd).
@ -1867,14 +1869,14 @@ Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
if (SExtOpnd->use_empty())
TPT.eraseInstruction(SExtOpnd);
// Check if the sext is still needed.
if (SExt->getType() != SExt->getOperand(0)->getType())
return SExt;
// Check if the extension is still needed.
if (ExtInst->getType() != ExtInst->getOperand(0)->getType())
return ExtInst;
// At this point we have: sext ty opnd to ty.
// Reassign the uses of SExt to the opnd and remove SExt.
Value *NextVal = SExt->getOperand(0);
TPT.eraseInstruction(SExt, NextVal);
// At this point we have: ext ty opnd to ty.
// Reassign the uses of ExtInst to the opnd and remove ExtInst.
Value *NextVal = ExtInst->getOperand(0);
TPT.eraseInstruction(ExtInst, NextVal);
return NextVal;
}

63
test/CodeGen/X86/codegen-prepare-addrmode-sext.ll
View File

@ -336,3 +336,66 @@ end:
%final = load i32* %addr
ret i32 %final
}
%struct.dns_packet = type { i32, i32, %union.anon }
%union.anon = type { i32 }
@a = common global i32 0, align 4
@b = common global i16 0, align 2
; We used to crash on this function because we did not return the right
; promoted instruction for %conv.i.
; Make sure we generate the right code now.
; CHECK-LABEL: @fn3
; %conv.i is used twice and only one of its use is being promoted.
; Use it at the starting point for the matching.
; CHECK: %conv.i = zext i16 [[PLAIN_OPND:%[.a-zA-Z_0-9-]+]] to i32
; CHECK-NEXT: [[PROMOTED_CONV:%[.a-zA-Z_0-9-]+]] = zext i16 [[PLAIN_OPND]] to i64
; CHECK-NEXT: [[BASE:%[a-zA-Z_0-9-]+]] = ptrtoint %struct.dns_packet* %P to i64
; CHECK-NEXT: [[ADD:%[a-zA-Z_0-9-]+]] = add i64 [[BASE]], [[PROMOTED_CONV]]
; CHECK-NEXT: [[ADDR:%[a-zA-Z_0-9-]+]] = add i64 [[ADD]], 7
; CHECK-NEXT: [[CAST:%[a-zA-Z_0-9-]+]] = inttoptr i64 [[ADDR]] to i8*
; CHECK-NEXT: load i8* [[CAST]], align 1
define signext i16 @fn3(%struct.dns_packet* nocapture readonly %P) {
entry:
%tmp = getelementptr inbounds %struct.dns_packet* %P, i64 0, i32 2
%data.i.i = bitcast %union.anon* %tmp to [0 x i8]*
br label %while.body.i.i
while.body.i.i: ; preds = %while.body.i.i, %entry
%src.addr.0.i.i = phi i16 [ 0, %entry ], [ %inc.i.i, %while.body.i.i ]
%inc.i.i = add i16 %src.addr.0.i.i, 1
%idxprom.i.i = sext i16 %src.addr.0.i.i to i64
%arrayidx.i.i = getelementptr inbounds [0 x i8]* %data.i.i, i64 0, i64 %idxprom.i.i
%tmp1 = load i8* %arrayidx.i.i, align 1
%conv2.i.i = zext i8 %tmp1 to i32
%and.i.i = and i32 %conv2.i.i, 15
store i32 %and.i.i, i32* @a, align 4
%tobool.i.i = icmp eq i32 %and.i.i, 0
br i1 %tobool.i.i, label %while.body.i.i, label %fn1.exit.i
fn1.exit.i: ; preds = %while.body.i.i
%inc.i.i.lcssa = phi i16 [ %inc.i.i, %while.body.i.i ]
%conv.i = zext i16 %inc.i.i.lcssa to i32
%sub.i = add nsw i32 %conv.i, -1
%idxprom.i = sext i32 %sub.i to i64
%arrayidx.i = getelementptr inbounds [0 x i8]* %data.i.i, i64 0, i64 %idxprom.i
%tmp2 = load i8* %arrayidx.i, align 1
%conv2.i = sext i8 %tmp2 to i16
store i16 %conv2.i, i16* @b, align 2
%sub4.i = sub nsw i32 0, %conv.i
%conv5.i = zext i16 %conv2.i to i32
%cmp.i = icmp sgt i32 %conv5.i, %sub4.i
br i1 %cmp.i, label %if.then.i, label %fn2.exit
if.then.i: ; preds = %fn1.exit.i
%end.i = getelementptr inbounds %struct.dns_packet* %P, i64 0, i32 1
%tmp3 = load i32* %end.i, align 4
%sub7.i = add i32 %tmp3, 65535
%conv8.i = trunc i32 %sub7.i to i16
br label %fn2.exit
fn2.exit: ; preds = %if.then.i, %fn1.exit.i
%retval.0.i = phi i16 [ %conv8.i, %if.then.i ], [ undef, %fn1.exit.i ]
ret i16 %retval.0.i
}