[NFC][InstCombine] '(Op1 & С) - Op1' pattern tests (PR44427)

llvm/test/Transforms/InstCombine/hoist-negation-out-of-bias-calculation-with-constant.ll

+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S < %s -instcombine | FileCheck %s
+
+; Fold
+;   (X & C) - X
+; to
+;   - (X & ~C)
+;
+; This allows us to possibly hoist said negation further out,
+; and decreases use count of X.
+
+; https://bugs.llvm.org/show_bug.cgi?id=44427
+
+; Base tests
+
+define i8 @t0(i8 %x) {
+; CHECK-LABEL: @t0(
+; CHECK-NEXT:    [[UNBIASEDX:%.*]] = and i8 [[X:%.*]], 42
+; CHECK-NEXT:    [[NEGBIAS:%.*]] = sub i8 [[UNBIASEDX]], [[X]]
+; CHECK-NEXT:    ret i8 [[NEGBIAS]]
+;
+  %unbiasedx = and i8 %x, 42
+  %negbias = sub i8 %unbiasedx, %x
+  ret i8 %negbias
+}
+
+define <2 x i8> @t1_vec(<2 x i8> %x) {
+; CHECK-LABEL: @t1_vec(
+; CHECK-NEXT:    [[UNBIASEDX:%.*]] = and <2 x i8> [[X:%.*]], <i8 42, i8 42>
+; CHECK-NEXT:    [[NEGBIAS:%.*]] = sub <2 x i8> [[UNBIASEDX]], [[X]]
+; CHECK-NEXT:    ret <2 x i8> [[NEGBIAS]]
+;
+  %unbiasedx = and <2 x i8> %x, <i8 42, i8 42>
+  %negbias = sub <2 x i8> %unbiasedx, %x
+  ret <2 x i8> %negbias
+}
+
+define <2 x i8> @t2_vec_undef(<2 x i8> %x) {
+; CHECK-LABEL: @t2_vec_undef(
+; CHECK-NEXT:    [[UNBIASEDX:%.*]] = and <2 x i8> [[X:%.*]], <i8 42, i8 undef>
+; CHECK-NEXT:    [[NEGBIAS:%.*]] = sub <2 x i8> [[UNBIASEDX]], [[X]]
+; CHECK-NEXT:    ret <2 x i8> [[NEGBIAS]]
+;
+  %unbiasedx = and <2 x i8> %x, <i8 42, i8 undef>
+  %negbias = sub <2 x i8> %unbiasedx, %x
+  ret <2 x i8> %negbias
+}
+
+define <2 x i8> @t3_vec_nonsplat(<2 x i8> %x) {
+; CHECK-LABEL: @t3_vec_nonsplat(
+; CHECK-NEXT:    [[UNBIASEDX:%.*]] = and <2 x i8> [[X:%.*]], <i8 42, i8 44>
+; CHECK-NEXT:    [[NEGBIAS:%.*]] = sub <2 x i8> [[UNBIASEDX]], [[X]]
+; CHECK-NEXT:    ret <2 x i8> [[NEGBIAS]]
+;
+  %unbiasedx = and <2 x i8> %x, <i8 42, i8 44>
+  %negbias = sub <2 x i8> %unbiasedx, %x
+  ret <2 x i8> %negbias
+}
+
+; Extra uses always prevent fold
+
+declare void @use8(i8)
+
+define i8 @n4_extrause(i8 %x) {
+; CHECK-LABEL: @n4_extrause(
+; CHECK-NEXT:    [[UNBIASEDX:%.*]] = and i8 [[X:%.*]], 42
+; CHECK-NEXT:    call void @use8(i8 [[UNBIASEDX]])
+; CHECK-NEXT:    [[NEGBIAS:%.*]] = sub i8 [[UNBIASEDX]], [[X]]
+; CHECK-NEXT:    ret i8 [[NEGBIAS]]
+;
+  %unbiasedx = and i8 %x, 42
+  call void @use8(i8 %unbiasedx)
+  %negbias = sub i8 %unbiasedx, %x
+  ret i8 %negbias
+}
+
+; Negative tests
+
+define i8 @n5(i8 %x) {
+; CHECK-LABEL: @n5(
+; CHECK-NEXT:    [[NEGBIAS:%.*]] = and i8 [[X:%.*]], -43
+; CHECK-NEXT:    ret i8 [[NEGBIAS]]
+;
+  %unbiasedx = and i8 %x, 42
+  %negbias = sub i8 %x, %unbiasedx ; wrong order
+  ret i8 %negbias
+}
+
+define i8 @n6(i8 %x0, i8 %x1) {
+; CHECK-LABEL: @n6(
+; CHECK-NEXT:    [[UNBIASEDX:%.*]] = and i8 [[X1:%.*]], 42
+; CHECK-NEXT:    [[NEGBIAS:%.*]] = sub i8 [[UNBIASEDX]], [[X0:%.*]]
+; CHECK-NEXT:    ret i8 [[NEGBIAS]]
+;
+  %unbiasedx = and i8 %x1, 42 ; not %x0
+  %negbias = sub i8 %unbiasedx, %x0 ; not %x1
+  ret i8 %negbias
+}