[ARM64] Fix immediate cost calculation for types larger than i64.

The immediate cost calculation code was hitting an assertion in the included
test case, because APInt was still internally 128-bits. Truncating it to 64-bits
fixed the issue.

Fixes <rdar://problem/16572521>.

llvm-svn: 205947

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM64/ARM64TargetTransformInfo.cpp b/llvm/lib/Target/ARM64/ARM64TargetTransformInfo.cpp
index 8a6253d7681..5323b8965f4 100644
--- a/llvm/lib/Target/ARM64/ARM64TargetTransformInfo.cpp
+++ b/llvm/lib/Target/ARM64/ARM64TargetTransformInfo.cpp
@@ -166,7 +166,7 @@ unsigned ARM64TTI::getIntImmCost(const APInt &Imm, Type *Ty) const {
   // chunk.
   unsigned Cost = 0;
   for (unsigned ShiftVal = 0; ShiftVal < BitSize; ShiftVal += 64) {
-    APInt Tmp = ImmVal.ashr(ShiftVal).getLoBits(64);
+    APInt Tmp = ImmVal.ashr(ShiftVal).sextOrTrunc(64);
     int64_t Val = Tmp.getSExtValue();
     Cost += getIntImmCost(Val);
   }