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[AArch64] Fix a type conversion bug for anlyzing compare.

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The bug can cause spec2006/483.xalancbmk failure.

Patched by David Xu.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215206 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jiangning Liu 2014-08-08 14:19:29 +00:00
parent 82acfbfe86
commit 3b85f30319
2 changed files with 45 additions and 4 deletions
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17
lib/Target/AArch64/AArch64InstrInfo.cpp
View File

@ -641,7 +641,8 @@ bool AArch64InstrInfo::analyzeCompare(const MachineInstr *MI, unsigned &SrcReg,
SrcReg = MI->getOperand(1).getReg();
SrcReg2 = 0;
CmpMask = ~0;
CmpValue = MI->getOperand(2).getImm();
// FIXME: In order to convert CmpValue to 0 or 1
CmpValue = (MI->getOperand(2).getImm() != 0);
return true;
case AArch64::ANDSWri:
case AArch64::ANDSXri:
@ -650,9 +651,14 @@ bool AArch64InstrInfo::analyzeCompare(const MachineInstr *MI, unsigned &SrcReg,
SrcReg = MI->getOperand(1).getReg();
SrcReg2 = 0;
CmpMask = ~0;
CmpValue = AArch64_AM::decodeLogicalImmediate(
MI->getOperand(2).getImm(),
MI->getOpcode() == AArch64::ANDSWri ? 32 : 64);
// FIXME:The return val type of decodeLogicalImmediate is uint64_t,
// while the type of CmpValue is int. When converting uint64_t to int,
// the high 32 bits of uint64_t will be lost.
// In fact it causes a bug in spec2006-483.xalancbmk
// CmpValue is only used to compare with zero in OptimizeCompareInstr
CmpValue = (AArch64_AM::decodeLogicalImmediate(
MI->getOperand(2).getImm(),
MI->getOpcode() == AArch64::ANDSWri ? 32 : 64) != 0);
return true;
}
@ -749,6 +755,9 @@ bool AArch64InstrInfo::optimizeCompareInstr(
}
// Continue only if we have a "ri" where immediate is zero.
// FIXME:CmpValue has already been converted to 0 or 1 in analyzeCompare
// function.
assert((CmpValue == 0 || CmpValue == 1) && "CmpValue must be 0 or 1!");
if (CmpValue != 0 || SrcReg2 != 0)
return false;

32
test/CodeGen/AArch64/analyzecmp.ll Normal file
View File

@ -0,0 +1,32 @@
; RUN: llc -O3 -mcpu=cortex-a57 < %s | FileCheck %s
; CHECK-LABLE: @test
; CHECK: tst [[CMP:x[0-9]+]], #0x8000000000000000
; CHECK: csel [[R0:x[0-9]+]], [[S0:x[0-9]+]], [[S1:x[0-9]+]], eq
; CHECK: csel [[R1:x[0-9]+]], [[S2:x[0-9]+]], [[S3:x[0-9]+]], eq
target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
target triple = "arm64--linux-gnueabi"
define void @test(i64 %a, i64* %ptr1, i64* %ptr2) #0 align 2 {
entry:
%conv = and i64 %a, 4294967295
%add = add nsw i64 %conv, -1
%div = sdiv i64 %add, 64
%rem = srem i64 %add, 64
%cmp = icmp slt i64 %rem, 0
br i1 %cmp, label %if.then, label %exit
if.then:
%add2 = add nsw i64 %rem, 64
%add3 = add i64 %div, -1
br label %exit
exit:
%__n = phi i64 [ %add3, %if.then ], [ %div, %entry ]
%__n.0 = phi i64 [ %add2, %if.then ], [ %rem, %entry ]
store i64 %__n, i64* %ptr1
store i64 %__n.0, i64* %ptr2
ret void
}