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[InstCombine] Add bswap test pattern using bitreverse intrinsic 

This is mainly to help with future better bitreverse folding support but we can test it via bswap matching for now.
This commit is contained in:
Simon Pilgrim 2020-10-26 14:13:02 +00:00
parent 0ca4124798
commit 16f126df43
1 changed files with 22 additions and 0 deletions
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22
llvm/test/Transforms/InstCombine/bswap.ll
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@ -535,6 +535,28 @@ define <2 x i32> @partial_bswap_vector(<2 x i32> %x) {
}
declare <2 x i32> @llvm.bswap.v2i32(<2 x i32>)
define i16 @partial_bitreverse(i16 %x) {
; CHECK-LABEL: @partial_bitreverse(
; CHECK-NEXT: [[REV:%.*]] = call i16 @llvm.bitreverse.i16(i16 [[X:%.*]])
; CHECK-NEXT: [[LO:%.*]] = and i16 [[REV]], 255
; CHECK-NEXT: [[HI:%.*]] = and i16 [[REV]], -256
; CHECK-NEXT: [[REVLO:%.*]] = call i16 @llvm.bitreverse.i16(i16 [[LO]])
; CHECK-NEXT: [[REVHI:%.*]] = call i16 @llvm.bitreverse.i16(i16 [[HI]])
; CHECK-NEXT: [[OR:%.*]] = call i16 @llvm.fshl.i16(i16 [[REVHI]], i16 [[REVLO]], i16 8)
; CHECK-NEXT: ret i16 [[OR]]
;
%rev= call i16 @llvm.bitreverse.i16(i16 %x)
%lo = and i16 %rev, 255
%hi = and i16 %rev, -256
%revlo = call i16 @llvm.bitreverse.i16(i16 %lo)
%revhi = call i16 @llvm.bitreverse.i16(i16 %hi)
%newlo = lshr i16 %revlo, 8
%newhi = shl i16 %revhi, 8
%or = or i16 %newlo, %newhi
ret i16 %or
}
declare i16 @llvm.bitreverse.i16(i16)
define i64 @bswap_and_mask_0(i64 %0) {
; CHECK-LABEL: @bswap_and_mask_0(
; CHECK-NEXT: [[TMP2:%.*]] = and i64 [[TMP0:%.*]], -72057594037927681