RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-19 11:02:59 +02:00
Code Issues Projects Releases Wiki Activity

[InstSimplify] Teach decomposeBitTestICmp to handle non-canonical compares

Browse Source 
This adds support non-canonical compare predicates. InstSimplify can't rely on canonicalization to have occurred.

Differential Revision: https://reviews.llvm.org/D36646

llvm-svn: 310893
This commit is contained in:
Craig Topper 2017-08-14 22:11:43 +00:00
parent 4947e7accc
commit 182026cffe
2 changed files with 36 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
lib/Analysis/CmpInstAnalysis.cpp
View File

@ -81,6 +81,13 @@ bool llvm::decomposeBitTestICmp(Value *LHS, Value *RHS,
Mask = APInt::getSignMask(C->getBitWidth());
Pred = ICmpInst::ICMP_NE;
break;
case ICmpInst::ICMP_SLE:
// X <= -1 is equivalent to (X & SignMask) != 0.
if (!C->isAllOnesValue())
return false;
Mask = APInt::getSignMask(C->getBitWidth());
Pred = ICmpInst::ICMP_NE;
break;
case ICmpInst::ICMP_SGT:
// X > -1 is equivalent to (X & SignMask) == 0.
if (!C->isAllOnesValue())
@ -88,6 +95,13 @@ bool llvm::decomposeBitTestICmp(Value *LHS, Value *RHS,
Mask = APInt::getSignMask(C->getBitWidth());
Pred = ICmpInst::ICMP_EQ;
break;
case ICmpInst::ICMP_SGE:
// X >= 0 is equivalent to (X & SignMask) == 0.
if (!C->isNullValue())
return false;
Mask = APInt::getSignMask(C->getBitWidth());
Pred = ICmpInst::ICMP_EQ;
break;
case ICmpInst::ICMP_ULT:
// X <u 2^n is equivalent to (X & ~(2^n-1)) == 0.
if (!C->isPowerOf2())
@ -95,6 +109,13 @@ bool llvm::decomposeBitTestICmp(Value *LHS, Value *RHS,
Mask = -*C;
Pred = ICmpInst::ICMP_EQ;
break;
case ICmpInst::ICMP_ULE:
// X <=u 2^n-1 is equivalent to (X & ~(2^n-1)) == 0.
if (!(*C + 1).isPowerOf2())
return false;
Mask = ~*C;
Pred = ICmpInst::ICMP_EQ;
break;
case ICmpInst::ICMP_UGT:
// X >u 2^n-1 is equivalent to (X & ~(2^n-1)) != 0.
if (!(*C + 1).isPowerOf2())
@ -102,6 +123,13 @@ bool llvm::decomposeBitTestICmp(Value *LHS, Value *RHS,
Mask = ~*C;
Pred = ICmpInst::ICMP_NE;
break;
case ICmpInst::ICMP_UGE:
// X >=u 2^n is equivalent to (X & ~(2^n-1)) != 0.
if (!C->isPowerOf2())
return false;
Mask = -*C;
Pred = ICmpInst::ICMP_NE;
break;
}
X = LHS;

28
test/Transforms/InstSimplify/select.ll
View File

@ -47,13 +47,10 @@ define i32 @test4(i32 %X) {
}
; Same as above, but the compare isn't canonical
; TODO: we should be able to simplify this
define i32 @test4noncanon(i32 %X) {
; CHECK-LABEL: @test4noncanon(
; CHECK-NEXT: [[CMP:%.*]] = icmp sle i32 [[X:%.*]], -1
; CHECK-NEXT: [[OR:%.*]] = or i32 [[X]], -2147483648
; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[X]], i32 [[OR]]
; CHECK-NEXT: ret i32 [[COND]]
; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], -2147483648
; CHECK-NEXT: ret i32 [[OR]]
;
%cmp = icmp sle i32 %X, -1
%or = or i32 %X, -2147483648
@ -114,13 +111,10 @@ define i32 @test9(i32 %X) {
}
; Same as above, but the compare isn't canonical
; TODO: we should be able to simplify this
define i32 @test9noncanon(i32 %X) {
; CHECK-LABEL: @test9noncanon(
; CHECK-NEXT: [[CMP:%.*]] = icmp sge i32 [[X:%.*]], 0
; CHECK-NEXT: [[OR:%.*]] = or i32 [[X]], -2147483648
; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[OR]], i32 [[X]]
; CHECK-NEXT: ret i32 [[COND]]
; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], -2147483648
; CHECK-NEXT: ret i32 [[OR]]
;
%cmp = icmp sge i32 %X, 0
%or = or i32 %X, -2147483648
@ -172,13 +166,10 @@ define i32 @test12(i32 %X) {
}
; Same as above, but the compare isn't canonical
; TODO: we should be able to simplify this
define i32 @test12noncanon(i32 %X) {
; CHECK-LABEL: @test12noncanon(
; CHECK-NEXT: [[CMP:%.*]] = icmp ule i32 [[X:%.*]], 3
; CHECK-NEXT: [[AND:%.*]] = and i32 [[X]], 3
; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[X]], i32 [[AND]]
; CHECK-NEXT: ret i32 [[COND]]
; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 3
; CHECK-NEXT: ret i32 [[AND]]
;
%cmp = icmp ule i32 %X, 3
%and = and i32 %X, 3
@ -198,13 +189,10 @@ define i32 @test13(i32 %X) {
}
; Same as above, but the compare isn't canonical
; TODO: we should be able to simplify this
define i32 @test13noncanon(i32 %X) {
; CHECK-LABEL: @test13noncanon(
; CHECK-NEXT: [[CMP:%.*]] = icmp uge i32 [[X:%.*]], 4
; CHECK-NEXT: [[AND:%.*]] = and i32 [[X]], 3
; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[AND]], i32 [[X]]
; CHECK-NEXT: ret i32 [[COND]]
; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 3
; CHECK-NEXT: ret i32 [[AND]]
;
%cmp = icmp uge i32 %X, 4
%and = and i32 %X, 3