[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
diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 4651a3a..6f33556 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -1384,16 +1384,15 @@
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)