[llvm] 3716a3c - [InstCombine] Folding multiuse `(icmp eq/ne (or X, Y), Y)` for 2 uses of `Y`

[Noah Goldstein via llvm-commits]

Author: Noah Goldstein
Date: 2024-06-06T12:42:07-05:00
New Revision: 3716a3c1bce4af81db6a95eee30e35b5b923e319

URL: https://github.com/llvm/llvm-project/commit/3716a3c1bce4af81db6a95eee30e35b5b923e319
DIFF: https://github.com/llvm/llvm-project/commit/3716a3c1bce4af81db6a95eee30e35b5b923e319.diff

LOG: [InstCombine] Folding multiuse `(icmp eq/ne (or X, Y), Y)` for 2 uses of `Y`

The fold will replace 2 uses of `Y` we should also do fold if `Y` has
2 uses (not only oneuse).

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D159062

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
    llvm/test/Transforms/InstCombine/icmp-of-or-x.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 803475bfaba5f..38c1c26445540 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -4795,7 +4795,7 @@ static Instruction *foldICmpOrXX(ICmpInst &I, const SimplifyQuery &Q,
   if (ICmpInst::isEquality(Pred) && Op0->hasOneUse()) {
     // icmp (X | Y) eq/ne Y --> (X & ~Y) eq/ne 0 if Y is freely invertible
     if (Value *NotOp1 =
-            IC.getFreelyInverted(Op1, Op1->hasOneUse(), &IC.Builder))
+            IC.getFreelyInverted(Op1, !Op1->hasNUsesOrMore(3), &IC.Builder))
       return new ICmpInst(Pred, IC.Builder.CreateAnd(A, NotOp1),
                           Constant::getNullValue(Op1->getType()));
     // icmp (X | Y) eq/ne Y --> (~X | Y) eq/ne -1 if X  is freely invertible.

diff  --git a/llvm/test/Transforms/InstCombine/icmp-of-or-x.ll b/llvm/test/Transforms/InstCombine/icmp-of-or-x.ll
index 9abcc1a7ed814..304874645d5dc 100644
--- a/llvm/test/Transforms/InstCombine/icmp-of-or-x.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-of-or-x.ll
@@ -376,10 +376,9 @@ define i1 @pr64610(ptr %b) {
 
 define i1 @icmp_eq_x_invertable_y2_todo(i8 %x, i1 %y, i8 %z) {
 ; CHECK-LABEL: @icmp_eq_x_invertable_y2_todo(
-; CHECK-NEXT:    [[ZZ:%.*]] = xor i8 [[Z:%.*]], -1
-; CHECK-NEXT:    [[YY:%.*]] = select i1 [[Y:%.*]], i8 7, i8 [[ZZ]]
-; CHECK-NEXT:    [[OR:%.*]] = or i8 [[YY]], [[X:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[YY]], [[OR]]
+; CHECK-NEXT:    [[TMP1:%.*]] = select i1 [[Y:%.*]], i8 -8, i8 [[Z:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = and i8 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[TMP2]], 0
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zz = xor i8 %z, -1