helper that skips creating a cast when it isn't necessary.
It's really somewhat concerning that this was caused by the the presence
of a no-op bitcast, but...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238642
91177308-0d34-0410-b5e6-
96231b3b80d8
; AVX1-LABEL: E5i:
; AVX1: ## BB#0: ## %entry
; AVX1-NEXT: vmovdqa (%rdi), %ymm0
-; AVX1-NEXT: vpaddw {{.*}}(%rip), %xmm0, %xmm0
; AVX1-NEXT: vmovaps (%rsi), %ymm1
+; AVX1-NEXT: vpaddw {{.*}}(%rip), %xmm0, %xmm0
; AVX1-NEXT: vinsertf128 $1, %xmm0, %ymm1, %ymm0
; AVX1-NEXT: retq
;