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| -rw-r--r-- | lib/Target/X86/README.txt | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index 08dcf5afc4..f58991728e 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -191,6 +191,18 @@ commutative, it is not matched with the load on both sides. The dag combiner should be made smart enough to cannonicalize the load into the RHS of a compare when it can invert the result of the compare for free. +How about intrinsics? An example is: + *res = _mm_mulhi_epu16(*A, _mm_mul_epu32(*B, *C)); + +compiles to + pmuludq (%eax), %xmm0 + movl 8(%esp), %eax + movdqa (%eax), %xmm1 + pmulhuw %xmm0, %xmm1 + +The transformation probably requires a X86 specific pass or a DAG combiner +target specific hook. + //===---------------------------------------------------------------------===// LSR should be turned on for the X86 backend and tuned to take advantage of its |