c72198079d
As discussed in D89952, instcombine can sometimes find a way to reduce similar patterns, but it is incomplete. InstSimplify uses the computeConstantRange() ValueTracking analysis via simplifyICmpWithConstant(), so we just need to fill in the max value of cttz to process any "icmp pred cttz(X), C" pattern (the min value is initialized to zero automatically). https://alive2.llvm.org/ce/z/Z_SLWZ Follow-up to D89976.
92 lines
2.9 KiB
LLVM
92 lines
2.9 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -S -instcombine | FileCheck %s
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declare i32 @llvm.ctpop.i32(i32)
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declare <2 x i32> @llvm.ctpop.v2i32(<2 x i32>)
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; PR43513
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; __builtin_popcount(i | -i) -> 32 - __builtin_cttz(i, false)
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define i32 @ctpop1(i32 %0) {
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; CHECK-LABEL: @ctpop1(
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; CHECK-NEXT: [[TMP2:%.*]] = call i32 @llvm.cttz.i32(i32 [[TMP0:%.*]], i1 false), !range !0
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; CHECK-NEXT: ret i32 [[TMP2]]
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;
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%2 = sub i32 0, %0
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%3 = or i32 %0, %2
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%4 = tail call i32 @llvm.ctpop.i32(i32 %3)
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%5 = sub i32 32, %4
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ret i32 %5
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}
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define <2 x i32> @ctpop1v(<2 x i32> %0) {
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; CHECK-LABEL: @ctpop1v(
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; CHECK-NEXT: [[TMP2:%.*]] = call <2 x i32> @llvm.cttz.v2i32(<2 x i32> [[TMP0:%.*]], i1 false)
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; CHECK-NEXT: [[TMP3:%.*]] = sub nuw nsw <2 x i32> <i32 32, i32 32>, [[TMP2]]
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; CHECK-NEXT: ret <2 x i32> [[TMP3]]
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;
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%2 = sub <2 x i32> zeroinitializer, %0
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%3 = or <2 x i32> %2, %0
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%4 = tail call <2 x i32> @llvm.ctpop.v2i32(<2 x i32> %3)
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ret <2 x i32> %4
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}
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define i32 @ctpop1_multiuse(i32 %0) {
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; CHECK-LABEL: @ctpop1_multiuse(
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; CHECK-NEXT: [[TMP2:%.*]] = sub i32 0, [[TMP0:%.*]]
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; CHECK-NEXT: [[TMP3:%.*]] = or i32 [[TMP2]], [[TMP0]]
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; CHECK-NEXT: [[TMP4:%.*]] = tail call i32 @llvm.ctpop.i32(i32 [[TMP3]]), !range !0
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; CHECK-NEXT: [[TMP5:%.*]] = sub nuw nsw i32 32, [[TMP4]]
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; CHECK-NEXT: [[TMP6:%.*]] = add i32 [[TMP5]], [[TMP3]]
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; CHECK-NEXT: ret i32 [[TMP6]]
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;
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%2 = sub i32 0, %0
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%3 = or i32 %0, %2
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%4 = tail call i32 @llvm.ctpop.i32(i32 %3)
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%5 = sub i32 32, %4
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%6 = add i32 %5, %3
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ret i32 %6
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}
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; PR43513
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; __builtin_popcount(~i & (i-1)) -> __builtin_cttz(i, false)
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define i32 @ctpop2(i32 %0) {
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; CHECK-LABEL: @ctpop2(
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; CHECK-NEXT: [[TMP2:%.*]] = call i32 @llvm.cttz.i32(i32 [[TMP0:%.*]], i1 false), !range !0
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; CHECK-NEXT: ret i32 [[TMP2]]
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;
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%2 = xor i32 %0, -1
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%3 = sub i32 %0, 1
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%4 = and i32 %3, %2
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%5 = tail call i32 @llvm.ctpop.i32(i32 %4)
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ret i32 %5
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}
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define <2 x i32> @ctpop2v(<2 x i32> %0) {
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; CHECK-LABEL: @ctpop2v(
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; CHECK-NEXT: [[TMP2:%.*]] = call <2 x i32> @llvm.cttz.v2i32(<2 x i32> [[TMP0:%.*]], i1 false)
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; CHECK-NEXT: ret <2 x i32> [[TMP2]]
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;
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%2 = xor <2 x i32> %0, <i32 -1, i32 -1>
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%3 = add <2 x i32> %0, <i32 -1, i32 -1>
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%4 = and <2 x i32> %2, %3
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%5 = tail call <2 x i32> @llvm.ctpop.v2i32(<2 x i32> %4)
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ret <2 x i32> %5
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}
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define i32 @ctpop2_multiuse(i32 %0) {
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; CHECK-LABEL: @ctpop2_multiuse(
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; CHECK-NEXT: [[TMP2:%.*]] = xor i32 [[TMP0:%.*]], -1
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; CHECK-NEXT: [[TMP3:%.*]] = add i32 [[TMP0]], -1
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; CHECK-NEXT: [[TMP4:%.*]] = and i32 [[TMP3]], [[TMP2]]
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; CHECK-NEXT: [[TMP5:%.*]] = call i32 @llvm.cttz.i32(i32 [[TMP0]], i1 false), !range !0
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; CHECK-NEXT: [[TMP6:%.*]] = add i32 [[TMP5]], [[TMP4]]
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; CHECK-NEXT: ret i32 [[TMP6]]
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;
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%2 = xor i32 %0, -1
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%3 = sub i32 %0, 1
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%4 = and i32 %3, %2
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%5 = tail call i32 @llvm.ctpop.i32(i32 %4)
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%6 = add i32 %5, %4
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ret i32 %6
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}
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