llvm/test/Transforms/InstCombine/demorgan-zext.ll
Sanjay Patel a2db716bbb [InstCombine] LogicOpc (zext X), C --> zext (LogicOpc X, C) (PR28476)
The benefits of this change include:
1. Remove DeMorgan-matching code that was added specifically to work-around 
   the missing transform in http://reviews.llvm.org/rL248634.
2. Makes the DeMorgan transform work for vectors too.
3. Fix PR28476: https://llvm.org/bugs/show_bug.cgi?id=28476

Extending this transform to other casts and other associative operators may
be useful too. See https://reviews.llvm.org/D22421 for a prerequisite for
doing that though.

Differential Revision: https://reviews.llvm.org/D22271



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276221 91177308-0d34-0410-b5e6-96231b3b80d8
2016-07-21 00:24:18 +00:00

82 lines
2.7 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
; PR22723: Recognize De Morgan's Laws when obfuscated by zexts.
define i32 @demorgan_or(i1 %X, i1 %Y) {
; CHECK-LABEL: @demorgan_or(
; CHECK-NEXT: [[OR1_DEMORGAN:%.*]] = and i1 %X, %Y
; CHECK-NEXT: [[OR1:%.*]] = xor i1 [[OR1_DEMORGAN]], true
; CHECK-NEXT: [[OR:%.*]] = zext i1 [[OR:%.*]]1 to i32
; CHECK-NEXT: ret i32 [[OR]]
;
%zextX = zext i1 %X to i32
%zextY = zext i1 %Y to i32
%notX = xor i32 %zextX, 1
%notY = xor i32 %zextY, 1
%or = or i32 %notX, %notY
ret i32 %or
}
define i32 @demorgan_and(i1 %X, i1 %Y) {
; CHECK-LABEL: @demorgan_and(
; CHECK-NEXT: [[AND1_DEMORGAN:%.*]] = or i1 %X, %Y
; CHECK-NEXT: [[AND1:%.*]] = xor i1 [[AND1_DEMORGAN]], true
; CHECK-NEXT: [[AND:%.*]] = zext i1 [[AND:%.*]]1 to i32
; CHECK-NEXT: ret i32 [[AND]]
;
%zextX = zext i1 %X to i32
%zextY = zext i1 %Y to i32
%notX = xor i32 %zextX, 1
%notY = xor i32 %zextY, 1
%and = and i32 %notX, %notY
ret i32 %and
}
define <2 x i32> @demorgan_or_vec(<2 x i1> %X, <2 x i1> %Y) {
; CHECK-LABEL: @demorgan_or_vec(
; CHECK-NEXT: [[OR1_DEMORGAN:%.*]] = and <2 x i1> %X, %Y
; CHECK-NEXT: [[OR1:%.*]] = xor <2 x i1> [[OR1_DEMORGAN]], <i1 true, i1 true>
; CHECK-NEXT: [[OR:%.*]] = zext <2 x i1> [[OR:%.*]]1 to <2 x i32>
; CHECK-NEXT: ret <2 x i32> [[OR]]
;
%zextX = zext <2 x i1> %X to <2 x i32>
%zextY = zext <2 x i1> %Y to <2 x i32>
%notX = xor <2 x i32> %zextX, <i32 1, i32 1>
%notY = xor <2 x i32> %zextY, <i32 1, i32 1>
%or = or <2 x i32> %notX, %notY
ret <2 x i32> %or
}
define <2 x i32> @demorgan_and_vec(<2 x i1> %X, <2 x i1> %Y) {
; CHECK-LABEL: @demorgan_and_vec(
; CHECK-NEXT: [[AND1_DEMORGAN:%.*]] = or <2 x i1> %X, %Y
; CHECK-NEXT: [[AND1:%.*]] = xor <2 x i1> [[AND1_DEMORGAN]], <i1 true, i1 true>
; CHECK-NEXT: [[AND:%.*]] = zext <2 x i1> [[AND:%.*]]1 to <2 x i32>
; CHECK-NEXT: ret <2 x i32> [[AND]]
;
%zextX = zext <2 x i1> %X to <2 x i32>
%zextY = zext <2 x i1> %Y to <2 x i32>
%notX = xor <2 x i32> %zextX, <i32 1, i32 1>
%notY = xor <2 x i32> %zextY, <i32 1, i32 1>
%and = and <2 x i32> %notX, %notY
ret <2 x i32> %and
}
define i32 @PR28476(i32 %x, i32 %y) {
; CHECK-LABEL: @PR28476(
; CHECK-NEXT: [[NOTLHS:%.*]] = icmp eq i32 %x, 0
; CHECK-NEXT: [[NOTRHS:%.*]] = icmp eq i32 %y, 0
; CHECK-NEXT: [[TMP1:%.*]] = or i1 [[NOTRHS]], [[NOTLHS]]
; CHECK-NEXT: [[COND:%.*]] = zext i1 [[TMP1]] to i32
; CHECK-NEXT: ret i32 [[COND]]
;
%cmp0 = icmp ne i32 %x, 0
%cmp1 = icmp ne i32 %y, 0
%and = and i1 %cmp0, %cmp1
%zext = zext i1 %and to i32
%cond = xor i32 %zext, 1
ret i32 %cond
}