[Thumb1] Fix cost calculation for complemented immediates

Materializing something like "-3" can be done as 2 instructions:
  MOV r0, #3
  MVN r0, r0

This has a cost of 2, not 3. It looks like we were already trying to detect this pattern in TII::getIntImmCost(), but were taking the complement of the zero-extended value instead of the sign-extended value which is unlikely to ever produce a number < 256.

There were no tests failing after changing this... :/

llvm-svn: 280928

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
index 13c5dc61acd..2d44adc9951 100644
--- a/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMTargetTransformInfo.cpp
@@ -41,7 +41,7 @@ int ARMTTIImpl::getIntImmCost(const APInt &Imm, Type *Ty) {
   // Thumb1.
   if (SImmVal >= 0 && SImmVal < 256)
     return 1;
-  if ((~ZImmVal < 256) || ARM_AM::isThumbImmShiftedVal(ZImmVal))
+  if ((~SImmVal < 256) || ARM_AM::isThumbImmShiftedVal(ZImmVal))
     return 2;
   // Load from constantpool.
   return 3;