[PATCH] D100095: [InstCombine] Conditionally emitting nsw/nuw flags when combining two add operations

Mehrnoosh Heidarpour via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Fri Apr 9 12:16:15 PDT 2021


MehrHeidar updated this revision to Diff 336542.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100095/new/

https://reviews.llvm.org/D100095

Files:
  llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
  llvm/test/Transforms/InstCombine/icmp-add.ll


Index: llvm/test/Transforms/InstCombine/icmp-add.ll
===================================================================
--- llvm/test/Transforms/InstCombine/icmp-add.ll
+++ llvm/test/Transforms/InstCombine/icmp-add.ll
@@ -666,7 +666,7 @@
 
 define i1 @without_nsw_nuw(i8 %x, i8 %y) {
 ; CHECK-LABEL: @without_nsw_nuw(
-; CHECK-NEXT:    [[TMP1:%.*]] = add nsw i8 [[X:%.*]], 2
+; CHECK-NEXT:    [[TMP1:%.*]] = add i8 [[X:%.*]], 2
 ; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i8 [[TMP1]], [[Y:%.*]]
 ; CHECK-NEXT:    ret i1 [[TOBOOL]]
 ;
@@ -678,7 +678,7 @@
 
 define i1 @with_nsw_nuw(i8 %x, i8 %y) {
 ; CHECK-LABEL: @with_nsw_nuw(
-; CHECK-NEXT:    [[TMP1:%.*]] = add nsw i8 [[X:%.*]], 2
+; CHECK-NEXT:    [[TMP1:%.*]] = add nuw nsw i8 [[X:%.*]], 2
 ; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i8 [[TMP1]], [[Y:%.*]]
 ; CHECK-NEXT:    ret i1 [[TOBOOL]]
 ;
@@ -702,7 +702,7 @@
 
 define i1 @with_nsw_small(i8 %x, i8 %y) {
 ; CHECK-LABEL: @with_nsw_small(
-; CHECK-NEXT:    [[TMP1:%.*]] = add nsw i8 [[Y:%.*]], 2
+; CHECK-NEXT:    [[TMP1:%.*]] = add i8 [[Y:%.*]], 2
 ; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i8 [[TMP1]], [[X:%.*]]
 ; CHECK-NEXT:    ret i1 [[TOBOOL]]
 ;
@@ -714,7 +714,7 @@
 
 define i1 @with_nuw_large(i8 %x, i8 %y) {
 ; CHECK-LABEL: @with_nuw_large(
-; CHECK-NEXT:    [[TMP1:%.*]] = add nsw i8 [[X:%.*]], 2
+; CHECK-NEXT:    [[TMP1:%.*]] = add nuw i8 [[X:%.*]], 2
 ; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i8 [[TMP1]], [[Y:%.*]]
 ; CHECK-NEXT:    ret i1 [[TOBOOL]]
 ;
@@ -726,7 +726,7 @@
 
 define i1 @with_nuw_small(i8 %x, i8 %y) {
 ; CHECK-LABEL: @with_nuw_small(
-; CHECK-NEXT:    [[TMP1:%.*]] = add nsw i8 [[Y:%.*]], 2
+; CHECK-NEXT:    [[TMP1:%.*]] = add i8 [[Y:%.*]], 2
 ; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i8 [[TMP1]], [[X:%.*]]
 ; CHECK-NEXT:    ret i1 [[TOBOOL]]
 ;
Index: llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -3901,11 +3901,13 @@
           APInt AP2Abs = C2->getValue().abs();
           if (AP1Abs.uge(AP2Abs)) {
             ConstantInt *C3 = Builder.getInt(AP1 - AP2);
-            Value *NewAdd = Builder.CreateNSWAdd(A, C3);
+            Value *NewAdd = Builder.CreateAdd(
+                A, C3, "", BO0->hasNoUnsignedWrap(), BO0->hasNoSignedWrap());
             return new ICmpInst(Pred, NewAdd, C);
           } else {
             ConstantInt *C3 = Builder.getInt(AP2 - AP1);
-            Value *NewAdd = Builder.CreateNSWAdd(C, C3);
+            Value *NewAdd = Builder.CreateAdd(
+                C, C3, "", BO1->hasNoUnsignedWrap(), BO1->hasNoSignedWrap());
             return new ICmpInst(Pred, A, NewAdd);
           }
         }


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