RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-23 03:02:36 +01:00
Code Issues Projects Releases Wiki Activity

[InstCombine] Fold a & ~(a ^ b) to x & y

Browse Source 
```
----------------------------------------
define i32 @and_xor_not_common_op(i32 %a, i32 %b) {
%0:
  %b2 = xor i32 %b, 4294967295
  %t2 = xor i32 %a, %b2
  %t4 = and i32 %t2, %a
  ret i32 %t4
}
=>
define i32 @and_xor_not_common_op(i32 %a, i32 %b) {
%0:
  %t4 = and i32 %a, %b
  ret i32 %t4
}
Transformation seems to be correct!
```
This commit is contained in:
Roman Lebedev 2020-12-24 14:09:49 +03:00
parent 48560ac305
commit b911a4e6f2
2 changed files with 9 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
View File

@ -1883,6 +1883,13 @@ Instruction *InstCombinerImpl::visitAnd(BinaryOperator &I) {
if (match(Op0, m_OneUse(m_c_Xor(m_Specific(Op1), m_Value(B)))))
return BinaryOperator::CreateAnd(Op1, Builder.CreateNot(B));
// A & ~(A ^ B) --> A & B
if (match(Op1, m_Not(m_c_Xor(m_Specific(Op0), m_Value(B)))))
return BinaryOperator::CreateAnd(Op0, B);
// ~(A ^ B) & A --> A & B
if (match(Op0, m_Not(m_c_Xor(m_Specific(Op1), m_Value(B)))))
return BinaryOperator::CreateAnd(Op1, B);
// (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C
if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))

8
test/Transforms/InstCombine/and-xor-or.ll
View File

@ -116,9 +116,7 @@ define i32 @and_xor_not_common_op_extrause(i32 %a, i32 %b, i32* %dst) {
define i32 @and_not_xor_common_op(i32 %a, i32 %b) {
; CHECK-LABEL: @and_not_xor_common_op(
; CHECK-NEXT: [[B2:%.*]] = xor i32 [[B:%.*]], [[A:%.*]]
; CHECK-NEXT: [[T2:%.*]] = xor i32 [[B2]], -1
; CHECK-NEXT: [[T4:%.*]] = and i32 [[T2]], [[A]]
; CHECK-NEXT: [[T4:%.*]] = and i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: ret i32 [[T4]]
;
%b2 = xor i32 %b, %a
@ -131,9 +129,7 @@ declare i32 @gen32()
define i32 @and_not_xor_common_op_commutative(i32 %b) {
; CHECK-LABEL: @and_not_xor_common_op_commutative(
; CHECK-NEXT: [[A:%.*]] = call i32 @gen32()
; CHECK-NEXT: [[B2:%.*]] = xor i32 [[A]], [[B:%.*]]
; CHECK-NEXT: [[T2:%.*]] = xor i32 [[B2]], -1
; CHECK-NEXT: [[T4:%.*]] = and i32 [[A]], [[T2]]
; CHECK-NEXT: [[T4:%.*]] = and i32 [[A]], [[B:%.*]]
; CHECK-NEXT: ret i32 [[T4]]
;
%a = call i32 @gen32()