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[NFC][InstCombine] Tests for ((~x) + y) + 1 -> y - x fold fold (PR42459)
To be noted, this pattern is not unhandled by instcombine per-se, it is somehow does end up being folded when one runs opt -O3, but not if it's just -instcombine. Regardless, that fold is indirect, depends on some other folds, and is thus blind when there are extra uses. https://bugs.llvm.org/show_bug.cgi?id=42459 https://rise4fun.com/Alive/EPO0 llvm-svn: 364749
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‎llvm/test/Transforms/InstCombine/fold-inc-of-add-of-not-x-and-y-to-sub-x-from-y.ll

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt -instcombine -S < %s | FileCheck %s
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; Given:
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; add (add (xor %x, -1), %y), 1
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; Transform it to:
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; sub %y, %x
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;------------------------------------------------------------------------------;
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; Scalar tests
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;------------------------------------------------------------------------------;
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define i32 @t0(i32 %x, i32 %y) {
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; CHECK-LABEL: @t0(
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; CHECK-NEXT: [[T0:%.*]] = xor i32 [[X:%.*]], -1
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; CHECK-NEXT: [[T1:%.*]] = add i32 [[T0]], [[Y:%.*]]
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[T1]], 1
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; CHECK-NEXT: ret i32 [[T2]]
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;
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%t0 = xor i32 %x, -1
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%t1 = add i32 %t0, %y
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%t2 = add i32 %t1, 1
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ret i32 %t2
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}
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;------------------------------------------------------------------------------;
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; Vector tests
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;------------------------------------------------------------------------------;
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define <4 x i32> @t1_vec_splat(<4 x i32> %x, <4 x i32> %y) {
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; CHECK-LABEL: @t1_vec_splat(
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; CHECK-NEXT: [[T0:%.*]] = xor <4 x i32> [[X:%.*]], <i32 -1, i32 -1, i32 -1, i32 -1>
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; CHECK-NEXT: [[T1:%.*]] = add <4 x i32> [[T0]], [[Y:%.*]]
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; CHECK-NEXT: [[T2:%.*]] = add <4 x i32> [[T1]], <i32 1, i32 1, i32 1, i32 1>
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; CHECK-NEXT: ret <4 x i32> [[T2]]
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;
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%t0 = xor <4 x i32> %x, <i32 -1, i32 -1, i32 -1, i32 -1>
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%t1 = add <4 x i32> %t0, %y
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%t2 = add <4 x i32> %t1, <i32 1, i32 1, i32 1, i32 1>
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ret <4 x i32> %t2
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}
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define <4 x i32> @t2_vec_undef0(<4 x i32> %x, <4 x i32> %y) {
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; CHECK-LABEL: @t2_vec_undef0(
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; CHECK-NEXT: [[T0:%.*]] = xor <4 x i32> [[X:%.*]], <i32 -1, i32 -1, i32 undef, i32 -1>
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; CHECK-NEXT: [[T1:%.*]] = add <4 x i32> [[T0]], [[Y:%.*]]
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; CHECK-NEXT: [[T2:%.*]] = add <4 x i32> [[T1]], <i32 1, i32 1, i32 1, i32 1>
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; CHECK-NEXT: ret <4 x i32> [[T2]]
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;
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%t0 = xor <4 x i32> %x, <i32 -1, i32 -1, i32 undef, i32 -1>
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%t1 = add <4 x i32> %t0, %y
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%t2 = add <4 x i32> %t1, <i32 1, i32 1, i32 1, i32 1>
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ret <4 x i32> %t2
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}
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define <4 x i32> @t3_vec_undef1(<4 x i32> %x, <4 x i32> %y) {
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; CHECK-LABEL: @t3_vec_undef1(
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; CHECK-NEXT: [[T0:%.*]] = xor <4 x i32> [[X:%.*]], <i32 -1, i32 -1, i32 -1, i32 -1>
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; CHECK-NEXT: [[T1:%.*]] = add <4 x i32> [[T0]], [[Y:%.*]]
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; CHECK-NEXT: [[T2:%.*]] = add <4 x i32> [[T1]], <i32 1, i32 1, i32 undef, i32 1>
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; CHECK-NEXT: ret <4 x i32> [[T2]]
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;
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%t0 = xor <4 x i32> %x, <i32 -1, i32 -1, i32 -1, i32 -1>
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%t1 = add <4 x i32> %t0, %y
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%t2 = add <4 x i32> %t1, <i32 1, i32 1, i32 undef, i32 1>
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ret <4 x i32> %t2
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}
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define <4 x i32> @t4_vec_undef2(<4 x i32> %x, <4 x i32> %y) {
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; CHECK-LABEL: @t4_vec_undef2(
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; CHECK-NEXT: [[T0:%.*]] = xor <4 x i32> [[X:%.*]], <i32 -1, i32 -1, i32 undef, i32 -1>
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; CHECK-NEXT: [[T1:%.*]] = add <4 x i32> [[T0]], [[Y:%.*]]
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; CHECK-NEXT: [[T2:%.*]] = add <4 x i32> [[T1]], <i32 1, i32 1, i32 undef, i32 1>
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; CHECK-NEXT: ret <4 x i32> [[T2]]
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;
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%t0 = xor <4 x i32> %x, <i32 -1, i32 -1, i32 undef, i32 -1>
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%t1 = add <4 x i32> %t0, %y
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%t2 = add <4 x i32> %t1, <i32 1, i32 1, i32 undef, i32 1>
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ret <4 x i32> %t2
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}
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;------------------------------------------------------------------------------;
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; One-use tests
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;------------------------------------------------------------------------------;
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declare void @use32(i32)
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define i32 @t5(i32 %x, i32 %y) {
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; CHECK-LABEL: @t5(
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; CHECK-NEXT: [[T0:%.*]] = xor i32 [[X:%.*]], -1
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; CHECK-NEXT: call void @use32(i32 [[T0]])
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; CHECK-NEXT: [[T1:%.*]] = add i32 [[T0]], [[Y:%.*]]
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[T1]], 1
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; CHECK-NEXT: ret i32 [[T2]]
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;
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%t0 = xor i32 %x, -1
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call void @use32(i32 %t0)
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%t1 = add i32 %t0, %y
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%t2 = add i32 %t1, 1
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ret i32 %t2
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}
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define i32 @t6(i32 %x, i32 %y) {
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; CHECK-LABEL: @t6(
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; CHECK-NEXT: [[T0:%.*]] = xor i32 [[X:%.*]], -1
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; CHECK-NEXT: [[T1:%.*]] = add i32 [[T0]], [[Y:%.*]]
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; CHECK-NEXT: call void @use32(i32 [[T1]])
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[T1]], 1
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; CHECK-NEXT: ret i32 [[T2]]
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;
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%t0 = xor i32 %x, -1
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%t1 = add i32 %t0, %y
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call void @use32(i32 %t1)
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%t2 = add i32 %t1, 1
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ret i32 %t2
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}
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define i32 @t7(i32 %x, i32 %y) {
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; CHECK-LABEL: @t7(
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; CHECK-NEXT: [[T0:%.*]] = xor i32 [[X:%.*]], -1
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; CHECK-NEXT: call void @use32(i32 [[T0]])
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; CHECK-NEXT: [[T1:%.*]] = add i32 [[T0]], [[Y:%.*]]
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; CHECK-NEXT: call void @use32(i32 [[T1]])
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[T1]], 1
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; CHECK-NEXT: ret i32 [[T2]]
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;
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%t0 = xor i32 %x, -1
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call void @use32(i32 %t0)
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%t1 = add i32 %t0, %y
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call void @use32(i32 %t1)
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%t2 = add i32 %t1, 1
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ret i32 %t2
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}
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;------------------------------------------------------------------------------;
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; Commutativity
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;------------------------------------------------------------------------------;
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declare i32 @gen32()
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define i32 @t8_commutative(i32 %x) {
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; CHECK-LABEL: @t8_commutative(
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; CHECK-NEXT: [[Y:%.*]] = call i32 @gen32()
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; CHECK-NEXT: [[T0:%.*]] = xor i32 [[X:%.*]], -1
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; CHECK-NEXT: [[T1:%.*]] = add i32 [[Y]], [[T0]]
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[T1]], 1
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; CHECK-NEXT: ret i32 [[T2]]
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;
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%y = call i32 @gen32()
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%t0 = xor i32 %x, -1
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%t1 = add i32 %y, %t0 ; swapped
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%t2 = add i32 %t1, 1
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ret i32 %t2
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}
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;------------------------------------------------------------------------------;
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; Basic negative tests
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;------------------------------------------------------------------------------;
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define i32 @n9(i32 %x, i32 %y) {
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; CHECK-LABEL: @n9(
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; CHECK-NEXT: [[T0:%.*]] = xor i32 [[X:%.*]], 2147483647
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; CHECK-NEXT: [[T1:%.*]] = add i32 [[T0]], [[Y:%.*]]
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[T1]], 1
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; CHECK-NEXT: ret i32 [[T2]]
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;
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%t0 = xor i32 %x, 2147483647 ; not -1
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%t1 = add i32 %t0, %y
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%t2 = add i32 %t1, 1
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ret i32 %t2
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}
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define i32 @n10(i32 %x, i32 %y) {
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; CHECK-LABEL: @n10(
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; CHECK-NEXT: [[T0:%.*]] = xor i32 [[X:%.*]], -1
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; CHECK-NEXT: [[T1:%.*]] = add i32 [[T0]], [[Y:%.*]]
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[T1]], 2
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; CHECK-NEXT: ret i32 [[T2]]
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;
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%t0 = xor i32 %x, -1
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%t1 = add i32 %t0, %y
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%t2 = add i32 %t1, 2 ; not +1
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ret i32 %t2
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}

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