[fast-isel] Address Eli's comments for r152847. Specifically, add a test case

and still allow immediate encoding, just not with cmn.
rdar://11038907


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152869 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chad Rosier 2012-03-15 22:54:20 +00:00
parent 90d9e02285
commit 0ac754f6f4
2 changed files with 27 additions and 9 deletions

View File

@ -1384,16 +1384,15 @@ bool ARMFastISel::ARMEmitCmp(const Value *Src1Value, const Value *Src2Value,
SrcVT == MVT::i1) {
const APInt &CIVal = ConstInt->getValue();
Imm = (isZExt) ? (int)CIVal.getZExtValue() : (int)CIVal.getSExtValue();
// We can't encode LONG_MIN (i.e., 0x80000000) as an immediate because
// there is no way to represent 2147483648 as a signed 32-bit int.
if (Imm != (int)0x80000000) {
if (Imm < 0) {
isNegativeImm = true;
Imm = -Imm;
}
UseImm = isThumb2 ? (ARM_AM::getT2SOImmVal(Imm) != -1) :
(ARM_AM::getSOImmVal(Imm) != -1);
// For INT_MIN/LONG_MIN (i.e., 0x80000000) we need to use a cmp, rather
// then a cmn, because there is no way to represent 2147483648 as a
// signed 32-bit int.
if (Imm < 0 && Imm != (int)0x80000000) {
isNegativeImm = true;
Imm = -Imm;
}
UseImm = isThumb2 ? (ARM_AM::getT2SOImmVal(Imm) != -1) :
(ARM_AM::getSOImmVal(Imm) != -1);
}
} else if (const ConstantFP *ConstFP = dyn_cast<ConstantFP>(Src2Value)) {
if (SrcVT == MVT::f32 || SrcVT == MVT::f64)

View File

@ -229,3 +229,22 @@ if.then: ; preds = %entry
if.end: ; preds = %if.then, %entry
ret void
}
; rdar://11038907
; When comparing LONG_MIN/INT_MIN use a cmp instruction.
define void @t13() nounwind ssp {
entry:
; ARM: t13
; THUMB: t13
%cmp = icmp slt i32 -123, -2147483648
; ARM: cmp r{{[0-9]}}, #-2147483648
; THUMB: cmp.w r{{[0-9]}}, #-2147483648
br i1 %cmp, label %if.then, label %if.end
if.then: ; preds = %entry
ret void
if.end: ; preds = %entry
ret void
}