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https://github.com/RPCS3/llvm-mirror.git
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f2c914ad2f
This is based on the example/comments in: https://llvm.org/PR48984 I tried just lifting the restriction in computeKnownBitsFromShiftOperator() as suggested in the bug report, but that doesn't catch all of the cases shown here. I didn't step through to see exactly why that happened. But it seems like a reasonable compromise to cheaply check the special-case of shifting a constant. There's a slight regression on a cmp transform as noted, but this is likely the more important/common pattern, so we can fix that icmp pattern later if needed. Differential Revision: https://reviews.llvm.org/D95959
237 lines
8.1 KiB
LLVM
237 lines
8.1 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -instcombine -S | FileCheck %s
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; For pattern ((X l>> Y) & ~C) ==/!= 0; when C+1 is power of 2
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; it may be optimal to fold into (X l>> Y) </>= C+1
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; rather than X & (~C << Y) ==/!= 0
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; Scalar tests
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define i1 @scalar_i8_lshr_and_negC_eq(i8 %x, i8 %y) {
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; CHECK-LABEL: @scalar_i8_lshr_and_negC_eq(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i8 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp ult i8 [[LSHR]], 4
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i8 %x, %y
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%and = and i8 %lshr, 252 ; ~3
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%r = icmp eq i8 %and, 0
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ret i1 %r
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}
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define i1 @scalar_i16_lshr_and_negC_eq(i16 %x, i16 %y) {
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; CHECK-LABEL: @scalar_i16_lshr_and_negC_eq(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i16 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp ult i16 [[LSHR]], 128
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i16 %x, %y
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%and = and i16 %lshr, 65408 ; ~127
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%r = icmp eq i16 %and, 0
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ret i1 %r
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}
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define i1 @scalar_i32_lshr_and_negC_eq(i32 %x, i32 %y) {
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; CHECK-LABEL: @scalar_i32_lshr_and_negC_eq(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp ult i32 [[LSHR]], 262144
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i32 %x, %y
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%and = and i32 %lshr, 4294705152 ; ~262143
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%r = icmp eq i32 %and, 0
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ret i1 %r
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}
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define i1 @scalar_i64_lshr_and_negC_eq(i64 %x, i64 %y) {
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; CHECK-LABEL: @scalar_i64_lshr_and_negC_eq(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i64 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp ult i64 [[LSHR]], 8589934592
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i64 %x, %y
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%and = and i64 %lshr, 18446744065119617024 ; ~8589934591
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%r = icmp eq i64 %and, 0
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ret i1 %r
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}
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define i1 @scalar_i32_lshr_and_negC_ne(i32 %x, i32 %y) {
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; CHECK-LABEL: @scalar_i32_lshr_and_negC_ne(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp ugt i32 [[LSHR]], 262143
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i32 %x, %y
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%and = and i32 %lshr, 4294705152 ; ~262143
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%r = icmp ne i32 %and, 0 ; check 'ne' predicate
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ret i1 %r
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}
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; Vector tests
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define <4 x i1> @vec_4xi32_lshr_and_negC_eq(<4 x i32> %x, <4 x i32> %y) {
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; CHECK-LABEL: @vec_4xi32_lshr_and_negC_eq(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr <4 x i32> [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp ult <4 x i32> [[LSHR]], <i32 8, i32 8, i32 8, i32 8>
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; CHECK-NEXT: ret <4 x i1> [[R]]
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;
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%lshr = lshr <4 x i32> %x, %y
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%and = and <4 x i32> %lshr, <i32 4294967288, i32 4294967288, i32 4294967288, i32 4294967288> ; ~7
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%r = icmp eq <4 x i32> %and, <i32 0, i32 0, i32 0, i32 0>
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ret <4 x i1> %r
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}
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define <4 x i1> @vec_lshr_and_negC_eq_undef1(<4 x i32> %x, <4 x i32> %y) {
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; CHECK-LABEL: @vec_lshr_and_negC_eq_undef1(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr <4 x i32> [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[AND:%.*]] = and <4 x i32> [[LSHR]], <i32 -8, i32 undef, i32 -8, i32 -8>
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; CHECK-NEXT: [[R:%.*]] = icmp eq <4 x i32> [[AND]], zeroinitializer
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; CHECK-NEXT: ret <4 x i1> [[R]]
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;
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%lshr = lshr <4 x i32> %x, %y
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%and = and <4 x i32> %lshr, <i32 4294967288, i32 undef, i32 4294967288, i32 4294967288> ; ~7
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%r = icmp eq <4 x i32> %and, <i32 0, i32 0, i32 0, i32 0>
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ret <4 x i1> %r
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}
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define <4 x i1> @vec_lshr_and_negC_eq_undef2(<4 x i32> %x, <4 x i32> %y) {
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; CHECK-LABEL: @vec_lshr_and_negC_eq_undef2(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr <4 x i32> [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[AND:%.*]] = and <4 x i32> [[LSHR]], <i32 -8, i32 -8, i32 -8, i32 -8>
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; CHECK-NEXT: [[R:%.*]] = icmp eq <4 x i32> [[AND]], <i32 0, i32 0, i32 0, i32 undef>
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; CHECK-NEXT: ret <4 x i1> [[R]]
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;
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%lshr = lshr <4 x i32> %x, %y
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%and = and <4 x i32> %lshr, <i32 4294967288, i32 4294967288, i32 4294967288, i32 4294967288> ; ~7
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%r = icmp eq <4 x i32> %and, <i32 0, i32 0, i32 0, i32 undef>
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ret <4 x i1> %r
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}
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define <4 x i1> @vec_lshr_and_negC_eq_undef3(<4 x i32> %x, <4 x i32> %y) {
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; CHECK-LABEL: @vec_lshr_and_negC_eq_undef3(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr <4 x i32> [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[AND:%.*]] = and <4 x i32> [[LSHR]], <i32 -8, i32 -8, i32 undef, i32 -8>
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; CHECK-NEXT: [[R:%.*]] = icmp eq <4 x i32> [[AND]], <i32 0, i32 0, i32 0, i32 undef>
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; CHECK-NEXT: ret <4 x i1> [[R]]
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;
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%lshr = lshr <4 x i32> %x, %y
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%and = and <4 x i32> %lshr, <i32 4294967288, i32 4294967288, i32 undef, i32 4294967288> ; ~7
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%r = icmp eq <4 x i32> %and, <i32 0, i32 0, i32 0, i32 undef>
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ret <4 x i1> %r
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}
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; Extra use
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; Fold happened
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define i1 @scalar_lshr_and_negC_eq_extra_use_lshr(i32 %x, i32 %y, i32 %z, i32* %p) {
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; CHECK-LABEL: @scalar_lshr_and_negC_eq_extra_use_lshr(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[LSHR]], [[Z:%.*]]
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; CHECK-NEXT: store i32 [[XOR]], i32* [[P:%.*]], align 4
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; CHECK-NEXT: [[R:%.*]] = icmp ult i32 [[LSHR]], 8
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i32 %x, %y
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%xor = xor i32 %lshr, %z ; extra use of lshr
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store i32 %xor, i32* %p
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%and = and i32 %lshr, 4294967288 ; ~7
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%r = icmp eq i32 %and, 0
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ret i1 %r
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}
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; Not fold
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define i1 @scalar_lshr_and_negC_eq_extra_use_and(i32 %x, i32 %y, i32 %z, i32* %p) {
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; CHECK-LABEL: @scalar_lshr_and_negC_eq_extra_use_and(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[AND:%.*]] = and i32 [[LSHR]], -8
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; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[AND]], [[Z:%.*]]
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; CHECK-NEXT: store i32 [[MUL]], i32* [[P:%.*]], align 4
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; CHECK-NEXT: [[R:%.*]] = icmp eq i32 [[AND]], 0
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i32 %x, %y
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%and = and i32 %lshr, 4294967288 ; ~7
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%mul = mul i32 %and, %z ; extra use of and
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store i32 %mul, i32* %p
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%r = icmp eq i32 %and, 0
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ret i1 %r
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}
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; Not fold
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define i1 @scalar_lshr_and_negC_eq_extra_use_lshr_and(i32 %x, i32 %y, i32 %z, i32* %p, i32* %q) {
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; CHECK-LABEL: @scalar_lshr_and_negC_eq_extra_use_lshr_and(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[AND:%.*]] = and i32 [[LSHR]], -8
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; CHECK-NEXT: store i32 [[AND]], i32* [[P:%.*]], align 4
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; CHECK-NEXT: [[ADD:%.*]] = add i32 [[LSHR]], [[Z:%.*]]
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; CHECK-NEXT: store i32 [[ADD]], i32* [[Q:%.*]], align 4
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; CHECK-NEXT: [[R:%.*]] = icmp eq i32 [[AND]], 0
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i32 %x, %y
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%and = and i32 %lshr, 4294967288 ; ~7
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store i32 %and, i32* %p ; extra use of and
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%add = add i32 %lshr, %z ; extra use of lshr
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store i32 %add, i32* %q
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%r = icmp eq i32 %and, 0
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ret i1 %r
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}
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; Negative tests
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; TODO: This could be reduced to lshr+icmp ult.
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define i1 @scalar_i32_lshr_and_negC_eq_X_is_constant1(i32 %y) {
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; CHECK-LABEL: @scalar_i32_lshr_and_negC_eq_X_is_constant1(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i32 12345, [[Y:%.*]]
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; CHECK-NEXT: [[AND:%.*]] = and i32 [[LSHR]], 16376
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; CHECK-NEXT: [[R:%.*]] = icmp eq i32 [[AND]], 0
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i32 12345, %y
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%and = and i32 %lshr, 4294967288 ; ~7
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%r = icmp eq i32 %and, 0
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ret i1 %r
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}
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; TODO: This could be reduced to lshr+icmp ult.
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define i1 @scalar_i32_lshr_and_negC_eq_X_is_constant2(i32 %y) {
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; CHECK-LABEL: @scalar_i32_lshr_and_negC_eq_X_is_constant2(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i32 268435456, [[Y:%.*]]
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; CHECK-NEXT: [[AND:%.*]] = and i32 [[LSHR]], 536870904
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; CHECK-NEXT: [[R:%.*]] = icmp eq i32 [[AND]], 0
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i32 268435456, %y
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%and = and i32 %lshr, 4294967288 ; ~7
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%r = icmp eq i32 %and, 0
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ret i1 %r
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}
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; Check 'slt' predicate
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define i1 @scalar_i32_lshr_and_negC_slt(i32 %x, i32 %y) {
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; CHECK-LABEL: @scalar_i32_lshr_and_negC_slt(
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; CHECK-NEXT: [[LSHR:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp slt i32 [[LSHR]], 0
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; CHECK-NEXT: ret i1 [[R]]
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;
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%lshr = lshr i32 %x, %y
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%and = and i32 %lshr, 4294967288 ; ~7
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%r = icmp slt i32 %and, 0
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ret i1 %r
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}
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; Compare with nonzero
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define i1 @scalar_i32_lshr_and_negC_eq_nonzero(i32 %x, i32 %y) {
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; CHECK-LABEL: @scalar_i32_lshr_and_negC_eq_nonzero(
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; CHECK-NEXT: ret i1 false
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;
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%lshr = lshr i32 %x, %y
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%and = and i32 %lshr, 4294967288 ; ~7
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%r = icmp eq i32 %and, 1 ; should be comparing with 0
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ret i1 %r
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}
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