[ConstantHoisting][X86] Change the cost model to never hoist constants for types larger than i128.

Currently the X86 backend doesn't support types larger than i128 very well. For
example an i192 multiply will assert in codegen when the 2nd argument is a constant and the constant got hoisted.

This fix changes the cost model to never hoist constants for types larger than
i128. Once the codegen issues have been resolved, the cost model can be updated
to allow also larger types.

This is related to <rdar://problem/16954938>

llvm-svn: 209162

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/test/Transforms/ConstantHoisting/X86/large-immediate.ll b/llvm/test/Transforms/ConstantHoisting/X86/large-immediate.ll
index bd7fa40e9c5..e0af9c9be57 100644
--- a/llvm/test/Transforms/ConstantHoisting/X86/large-immediate.ll
+++ b/llvm/test/Transforms/ConstantHoisting/X86/large-immediate.ll
@@ -16,3 +16,12 @@ define i512 @test2(i512 %a) nounwind {
   %2 = ashr i512 %1, 504
   ret i512 %2
 }
+
+; Check that we don't hoist constants with a type larger than i128.
+define i196 @test3(i196 %a) nounwind {
+; CHECK-LABEL: test3
+; CHECK-NOT: %const = bitcast i196 2 to i196
+  %1 = mul i196 %a, 2
+  %2 = mul i196 %1, 2
+  ret i196 %2
+}