From 1d1515a9e28c7f32af548584ebed66cd8caae84f Mon Sep 17 00:00:00 2001 From: Craig Topper Date: Tue, 25 Aug 2020 18:20:41 -0700 Subject: [PATCH] [X86] Add an isel pattern for (i8 (trunc (i16 (bitconvert (v16i1 X))))) to avoid an extra EXTRACT_SUBREG Since we can only copy to GR32 we had to EXTRACT from GR32, but we would first go to GR16 and then the truncate would extra again to GR8. This adds a special case to go directly from GR32 to GR8. This would eventually get cleaned up, but though maybe we should avoid doing it in the first place. Our k-register handling is weird and we could probably stand to have some more special ISD nodes for the conversions so the i32 type would be explicit. --- llvm/lib/Target/X86/X86InstrAVX512.td | 2 ++ 1 file changed, 2 insertions(+) diff --git a/llvm/lib/Target/X86/X86InstrAVX512.td b/llvm/lib/Target/X86/X86InstrAVX512.td index 0514a3a..e1eb664 100644 --- a/llvm/lib/Target/X86/X86InstrAVX512.td +++ b/llvm/lib/Target/X86/X86InstrAVX512.td @@ -2884,6 +2884,8 @@ def : Pat<(v16i1 (bitconvert (i16 GR16:$src))), (COPY_TO_REGCLASS (i32 (INSERT_SUBREG (IMPLICIT_DEF), GR16:$src, sub_16bit)), VK16)>; def : Pat<(i16 (bitconvert (v16i1 VK16:$src))), (EXTRACT_SUBREG (i32 (COPY_TO_REGCLASS VK16:$src, GR32)), sub_16bit)>; +def : Pat<(i8 (trunc (i16 (bitconvert (v16i1 VK16:$src))))), + (EXTRACT_SUBREG (i32 (COPY_TO_REGCLASS VK16:$src, GR32)), sub_8bit)>; def : Pat<(v8i1 (bitconvert (i8 GR8:$src))), (COPY_TO_REGCLASS (i32 (INSERT_SUBREG (IMPLICIT_DEF), GR8:$src, sub_8bit)), VK8)>; -- 2.7.4