[PATCH] D125352: [InstCombine] fix sub(add(X,Y),umin(Y,Z)) --> add(X,usub.sat(Y,Z))

[Chenbing.Zheng via Phabricator via llvm-commits]

Chenbing.Zheng updated this revision to Diff 428837.
Chenbing.Zheng added a comment.

rebase and update tests


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D125352/new/

https://reviews.llvm.org/D125352

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
  llvm/test/Transforms/InstCombine/sub-minmax.ll


Index: llvm/test/Transforms/InstCombine/sub-minmax.ll
===================================================================
--- llvm/test/Transforms/InstCombine/sub-minmax.ll
+++ llvm/test/Transforms/InstCombine/sub-minmax.ll
@@ -762,9 +762,7 @@
   ret i8 %s
 }
 
-;
-; TODO: sub(add(X,Y),umin(Y,Z)) --> add(X,usubsat(Y,Z))
-;
+; sub(add(X,Y),umin(Y,Z)) --> add(X,usubsat(Y,Z))
 
 define i8 @sub_add_umin(i8 %x, i8 %y, i8 %z) {
 ; CHECK-LABEL: define {{[^@]+}}@sub_add_umin
@@ -782,7 +780,7 @@
 define i8 @sub_add_umin_commute_umin(i8 %x, i8 %y, i8 %z) {
 ; CHECK-LABEL: define {{[^@]+}}@sub_add_umin_commute_umin
 ; CHECK-SAME: (i8 [[X:%.*]], i8 [[Y:%.*]], i8 [[Z:%.*]]) {
-; CHECK-NEXT:    [[TMP1:%.*]] = call i8 @llvm.usub.sat.i8(i8 [[Z]], i8 [[Y]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call i8 @llvm.usub.sat.i8(i8 [[Y]], i8 [[Z]])
 ; CHECK-NEXT:    [[S:%.*]] = add i8 [[TMP1]], [[X]]
 ; CHECK-NEXT:    ret i8 [[S]]
 ;
@@ -808,7 +806,7 @@
 define i8 @sub_add_umin_commute_add_umin(i8 %x, i8 %y, i8 %z) {
 ; CHECK-LABEL: define {{[^@]+}}@sub_add_umin_commute_add_umin
 ; CHECK-SAME: (i8 [[X:%.*]], i8 [[Y:%.*]], i8 [[Z:%.*]]) {
-; CHECK-NEXT:    [[TMP1:%.*]] = call i8 @llvm.usub.sat.i8(i8 [[Z]], i8 [[Y]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call i8 @llvm.usub.sat.i8(i8 [[Y]], i8 [[Z]])
 ; CHECK-NEXT:    [[S:%.*]] = add i8 [[TMP1]], [[X]]
 ; CHECK-NEXT:    ret i8 [[S]]
 ;
Index: llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -2031,14 +2031,17 @@
 
     {
       // sub(add(X,Y),umin(Y,Z)) --> add(X,usub.sat(Y,Z))
-      // sub(add(X,Z),umin(Y,Z)) --> add(X,usub.sat(Y,Z))
+      // sub(add(X,Z),umin(Y,Z)) --> add(X,usub.sat(Z,Y))
       Value *X, *Y, *Z;
-      if (match(Op1, m_OneUse(m_UMin(m_Value(Y), m_Value(Z)))) &&
-          (match(Op0, m_OneUse(m_c_Add(m_Specific(Y), m_Value(X)))) ||
-           match(Op0, m_OneUse(m_c_Add(m_Specific(Z), m_Value(X)))))) {
-        Value *USub =
-            Builder.CreateIntrinsic(Intrinsic::usub_sat, I.getType(), {Y, Z});
-        return BinaryOperator::CreateAdd(X, USub);
+      if (match(Op1, m_OneUse(m_UMin(m_Value(Y), m_Value(Z))))) {
+        if (match(Op0, m_OneUse(m_c_Add(m_Specific(Y), m_Value(X)))))
+          return BinaryOperator::CreateAdd(
+              X, Builder.CreateIntrinsic(Intrinsic::usub_sat, I.getType(),
+                                         {Y, Z}));
+        if (match(Op0, m_OneUse(m_c_Add(m_Specific(Z), m_Value(X)))))
+          return BinaryOperator::CreateAdd(
+              X, Builder.CreateIntrinsic(Intrinsic::usub_sat, I.getType(),
+                                         {Z, Y}));
       }
     }
   }


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D125352.428837.patch
Type: text/x-patch
Size: 2793 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220512/0201c645/attachment.bin>