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[InstSimplify] fold srem with sext bool divisor 

llvm-svn: 335616
This commit is contained in:
Sanjay Patel 2018-06-26 15:32:54 +00:00
parent c307b00348
commit 2b7e31095d
2 changed files with 8 additions and 6 deletions
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6
llvm/lib/Analysis/InstructionSimplify.cpp
View File

@ -1099,6 +1099,12 @@ Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
/// If not, this returns null.
static Value *SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
unsigned MaxRecurse) {
// If the divisor is 0, the result is undefined, so assume the divisor is -1.
// srem Op0, (sext i1 X) --> srem Op0, -1 --> 0
Value *X;
if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))
return ConstantInt::getNullValue(Op0->getType());
return simplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse);
}

8
llvm/test/Transforms/InstSimplify/rem.ll
View File

@ -309,9 +309,7 @@ define i32 @rem10(i32 %x, i32 %y) {
define i32 @srem_with_sext_bool_divisor(i1 %x, i32 %y) {
; CHECK-LABEL: @srem_with_sext_bool_divisor(
; CHECK-NEXT: [[S:%.*]] = sext i1 [[X:%.*]] to i32
; CHECK-NEXT: [[R:%.*]] = srem i32 [[Y:%.*]], [[S]]
; CHECK-NEXT: ret i32 [[R]]
; CHECK-NEXT: ret i32 0
;
%s = sext i1 %x to i32
%r = srem i32 %y, %s
@ -320,9 +318,7 @@ define i32 @srem_with_sext_bool_divisor(i1 %x, i32 %y) {
define <2 x i32> @srem_with_sext_bool_divisor_vec(<2 x i1> %x, <2 x i32> %y) {
; CHECK-LABEL: @srem_with_sext_bool_divisor_vec(
; CHECK-NEXT: [[S:%.*]] = sext <2 x i1> [[X:%.*]] to <2 x i32>
; CHECK-NEXT: [[R:%.*]] = srem <2 x i32> [[Y:%.*]], [[S]]
; CHECK-NEXT: ret <2 x i32> [[R]]
; CHECK-NEXT: ret <2 x i32> zeroinitializer
;
%s = sext <2 x i1> %x to <2 x i32>
%r = srem <2 x i32> %y, %s