[llvm] b87a351 - [NFC][InstCombine] '(X & (- Y)) - X' pattern tests (PR44448)
Roman Lebedev via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 3 09:27:51 PST 2020
Author: Roman Lebedev
Date: 2020-01-03T20:27:17+03:00
New Revision: b87a351182cd7883080fe0e82c803db71ff2ba91
URL: https://github.com/llvm/llvm-project/commit/b87a351182cd7883080fe0e82c803db71ff2ba91
DIFF: https://github.com/llvm/llvm-project/commit/b87a351182cd7883080fe0e82c803db71ff2ba91.diff
LOG: [NFC][InstCombine] '(X & (- Y)) - X' pattern tests (PR44448)
As discussed in https://bugs.llvm.org/show_bug.cgi?id=44448,
we can hoist negation out of the pattern.
Added:
llvm/test/Transforms/InstCombine/hoist-negation-out-of-bias-calculation.ll
Modified:
Removed:
################################################################################
diff --git a/llvm/test/Transforms/InstCombine/hoist-negation-out-of-bias-calculation.ll b/llvm/test/Transforms/InstCombine/hoist-negation-out-of-bias-calculation.ll
new file mode 100644
index 000000000000..b0e8884cea06
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/hoist-negation-out-of-bias-calculation.ll
@@ -0,0 +1,158 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S < %s -instcombine | FileCheck %s
+
+; Fold
+; (X & (- Y)) - X
+; to
+; - (X & (Y - 1))
+;
+; This allows us to possibly hoist said negation further out.
+
+; https://bugs.llvm.org/show_bug.cgi?id=44448
+
+; Base tests
+
+define i8 @t0(i8 %x, i8 %y) {
+; CHECK-LABEL: @t0(
+; CHECK-NEXT: [[NEGY:%.*]] = sub i8 0, [[Y:%.*]]
+; CHECK-NEXT: [[UNBIASEDX:%.*]] = and i8 [[NEGY]], [[X:%.*]]
+; CHECK-NEXT: [[NEGBIAS:%.*]] = sub i8 [[UNBIASEDX]], [[X]]
+; CHECK-NEXT: ret i8 [[NEGBIAS]]
+;
+ %negy = sub i8 0, %y
+ %unbiasedx = and i8 %negy, %x
+ %negbias = sub i8 %unbiasedx, %x
+ ret i8 %negbias
+}
+
+declare i8 @gen8()
+
+define i8 @t1_commutative(i8 %y) {
+; CHECK-LABEL: @t1_commutative(
+; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
+; CHECK-NEXT: [[NEGY:%.*]] = sub i8 0, [[Y:%.*]]
+; CHECK-NEXT: [[UNBIASEDX:%.*]] = and i8 [[X]], [[NEGY]]
+; CHECK-NEXT: [[NEGBIAS:%.*]] = sub i8 [[UNBIASEDX]], [[X]]
+; CHECK-NEXT: ret i8 [[NEGBIAS]]
+;
+ %x = call i8 @gen8()
+ %negy = sub i8 0, %y
+ %unbiasedx = and i8 %x, %negy ; commutative, swapped
+ %negbias = sub i8 %unbiasedx, %x
+ ret i8 %negbias
+}
+
+define <2 x i8> @t2_vec(<2 x i8> %x, <2 x i8> %y) {
+; CHECK-LABEL: @t2_vec(
+; CHECK-NEXT: [[NEGY:%.*]] = sub <2 x i8> zeroinitializer, [[Y:%.*]]
+; CHECK-NEXT: [[UNBIASEDX:%.*]] = and <2 x i8> [[NEGY]], [[X:%.*]]
+; CHECK-NEXT: [[NEGBIAS:%.*]] = sub <2 x i8> [[UNBIASEDX]], [[X]]
+; CHECK-NEXT: ret <2 x i8> [[NEGBIAS]]
+;
+ %negy = sub <2 x i8> <i8 0, i8 0>, %y
+ %unbiasedx = and <2 x i8> %negy, %x
+ %negbias = sub <2 x i8> %unbiasedx, %x
+ ret <2 x i8> %negbias
+}
+
+define <2 x i8> @t3_vec_undef(<2 x i8> %x, <2 x i8> %y) {
+; CHECK-LABEL: @t3_vec_undef(
+; CHECK-NEXT: [[NEGY:%.*]] = sub <2 x i8> <i8 0, i8 undef>, [[Y:%.*]]
+; CHECK-NEXT: [[UNBIASEDX:%.*]] = and <2 x i8> [[NEGY]], [[X:%.*]]
+; CHECK-NEXT: [[NEGBIAS:%.*]] = sub <2 x i8> [[UNBIASEDX]], [[X]]
+; CHECK-NEXT: ret <2 x i8> [[NEGBIAS]]
+;
+ %negy = sub <2 x i8> <i8 0, i8 undef>, %y
+ %unbiasedx = and <2 x i8> %negy, %x
+ %negbias = sub <2 x i8> %unbiasedx, %x
+ ret <2 x i8> %negbias
+}
+
+; Extra uses always prevent fold
+
+declare void @use8(i8)
+
+define i8 @n4_extrause0(i8 %x, i8 %y) {
+; CHECK-LABEL: @n4_extrause0(
+; CHECK-NEXT: [[NEGY:%.*]] = sub i8 0, [[Y:%.*]]
+; CHECK-NEXT: call void @use8(i8 [[NEGY]])
+; CHECK-NEXT: [[UNBIASEDX:%.*]] = and i8 [[NEGY]], [[X:%.*]]
+; CHECK-NEXT: [[NEGBIAS:%.*]] = sub i8 [[UNBIASEDX]], [[X]]
+; CHECK-NEXT: ret i8 [[NEGBIAS]]
+;
+ %negy = sub i8 0, %y
+ call void @use8(i8 %negy)
+ %unbiasedx = and i8 %negy, %x
+ %negbias = sub i8 %unbiasedx, %x
+ ret i8 %negbias
+}
+define i8 @n5_extrause1(i8 %x, i8 %y) {
+; CHECK-LABEL: @n5_extrause1(
+; CHECK-NEXT: [[NEGY:%.*]] = sub i8 0, [[Y:%.*]]
+; CHECK-NEXT: [[UNBIASEDX:%.*]] = and i8 [[NEGY]], [[X:%.*]]
+; CHECK-NEXT: call void @use8(i8 [[UNBIASEDX]])
+; CHECK-NEXT: [[NEGBIAS:%.*]] = sub i8 [[UNBIASEDX]], [[X]]
+; CHECK-NEXT: ret i8 [[NEGBIAS]]
+;
+ %negy = sub i8 0, %y
+ %unbiasedx = and i8 %negy, %x
+ call void @use8(i8 %unbiasedx)
+ %negbias = sub i8 %unbiasedx, %x
+ ret i8 %negbias
+}
+define i8 @n6_extrause2(i8 %x, i8 %y) {
+; CHECK-LABEL: @n6_extrause2(
+; CHECK-NEXT: [[NEGY:%.*]] = sub i8 0, [[Y:%.*]]
+; CHECK-NEXT: call void @use8(i8 [[NEGY]])
+; CHECK-NEXT: [[UNBIASEDX:%.*]] = and i8 [[NEGY]], [[X:%.*]]
+; CHECK-NEXT: call void @use8(i8 [[UNBIASEDX]])
+; CHECK-NEXT: [[NEGBIAS:%.*]] = sub i8 [[UNBIASEDX]], [[X]]
+; CHECK-NEXT: ret i8 [[NEGBIAS]]
+;
+ %negy = sub i8 0, %y
+ call void @use8(i8 %negy)
+ %unbiasedx = and i8 %negy, %x
+ call void @use8(i8 %unbiasedx)
+ %negbias = sub i8 %unbiasedx, %x
+ ret i8 %negbias
+}
+
+; Negative tests
+
+define i8 @n7(i8 %x, i8 %y) {
+; CHECK-LABEL: @n7(
+; CHECK-NEXT: [[NEGY_NOT:%.*]] = add i8 [[Y:%.*]], -1
+; CHECK-NEXT: [[NEGBIAS:%.*]] = and i8 [[NEGY_NOT]], [[X:%.*]]
+; CHECK-NEXT: ret i8 [[NEGBIAS]]
+;
+ %negy = sub i8 0, %y
+ %unbiasedx = and i8 %negy, %x
+ %negbias = sub i8 %x, %unbiasedx ; wrong order
+ ret i8 %negbias
+}
+
+define i8 @n8(i8 %x, i8 %y) {
+; CHECK-LABEL: @n8(
+; CHECK-NEXT: [[NEGY:%.*]] = sub i8 1, [[Y:%.*]]
+; CHECK-NEXT: [[UNBIASEDX:%.*]] = and i8 [[NEGY]], [[X:%.*]]
+; CHECK-NEXT: [[NEGBIAS:%.*]] = sub i8 [[UNBIASEDX]], [[X]]
+; CHECK-NEXT: ret i8 [[NEGBIAS]]
+;
+ %negy = sub i8 1, %y ; not negation
+ %unbiasedx = and i8 %negy, %x
+ %negbias = sub i8 %unbiasedx, %x
+ ret i8 %negbias
+}
+
+define i8 @n9(i8 %x0, i8 %x1, i8 %y) {
+; CHECK-LABEL: @n9(
+; CHECK-NEXT: [[NEGY:%.*]] = sub i8 0, [[Y:%.*]]
+; CHECK-NEXT: [[UNBIASEDX:%.*]] = and i8 [[NEGY]], [[X1:%.*]]
+; CHECK-NEXT: [[NEGBIAS:%.*]] = sub i8 [[UNBIASEDX]], [[X0:%.*]]
+; CHECK-NEXT: ret i8 [[NEGBIAS]]
+;
+ %negy = sub i8 0, %y
+ %unbiasedx = and i8 %x1, %negy ; not %x0
+ %negbias = sub i8 %unbiasedx, %x0 ; not %x1
+ ret i8 %negbias
+}
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