[PATCH] D138700: [InstSimplify] Fold (X || Y) ? false && X --> false

[chenglin.bi via Phabricator via llvm-commits]

bcl5980 updated this revision to Diff 478310.
bcl5980 edited the summary of this revision.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D138700/new/

https://reviews.llvm.org/D138700

Files:
  llvm/lib/Analysis/InstructionSimplify.cpp
  llvm/test/Transforms/InstSimplify/select-logical.ll


Index: llvm/test/Transforms/InstSimplify/select-logical.ll
===================================================================
--- llvm/test/Transforms/InstSimplify/select-logical.ll
+++ llvm/test/Transforms/InstSimplify/select-logical.ll
@@ -202,9 +202,7 @@
 
 define i1 @or_select_false_x_case1(i1 %x, i1 %y) {
 ; CHECK-LABEL: @or_select_false_x_case1(
-; CHECK-NEXT:    [[OR:%.*]] = or i1 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[OR]], i1 false, i1 [[X]]
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %or = or i1 %x, %y
   %r = select i1 %or, i1 false, i1 %x
@@ -215,9 +213,7 @@
 
 define i1 @or_select_false_x_case2(i1 %x, i1 %y) {
 ; CHECK-LABEL: @or_select_false_x_case2(
-; CHECK-NEXT:    [[OR:%.*]] = or i1 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[OR]], i1 false, i1 [[Y]]
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %or = or i1 %x, %y
   %r = select i1 %or, i1 false, i1 %y
@@ -228,9 +224,7 @@
 
 define <2 x i1> @or_select_false_x_vector(<2 x i1> %x, <2 x i1> %y) {
 ; CHECK-LABEL: @or_select_false_x_vector(
-; CHECK-NEXT:    [[OR:%.*]] = or <2 x i1> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = select <2 x i1> [[OR]], <2 x i1> zeroinitializer, <2 x i1> [[X]]
-; CHECK-NEXT:    ret <2 x i1> [[R]]
+; CHECK-NEXT:    ret <2 x i1> zeroinitializer
 ;
   %or = or <2 x i1> %x, %y
   %r = select <2 x i1> %or, <2 x i1> <i1 false, i1 false>, <2 x i1> %x
@@ -254,9 +248,7 @@
 
 define i1 @logical_or_select_false_x_case1(i1 %x, i1 %y) {
 ; CHECK-LABEL: @logical_or_select_false_x_case1(
-; CHECK-NEXT:    [[OR:%.*]] = select i1 [[X:%.*]], i1 true, i1 [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[OR]], i1 false, i1 [[X]]
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %or = select i1 %x, i1 true, i1 %y
   %r = select i1 %or, i1 false, i1 %x
@@ -267,9 +259,7 @@
 
 define i1 @logical_or_select_false_x_case2(i1 %x, i1 %y) {
 ; CHECK-LABEL: @logical_or_select_false_x_case2(
-; CHECK-NEXT:    [[OR:%.*]] = select i1 [[Y:%.*]], i1 true, i1 [[X:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[OR]], i1 false, i1 [[X]]
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %or = select i1 %y, i1 true, i1 %x
   %r = select i1 %or, i1 false, i1 %x
@@ -280,9 +270,7 @@
 
 define <2 x i1> @logical_or_select_false_x_vector(<2 x i1> %x, <2 x i1> %y) {
 ; CHECK-LABEL: @logical_or_select_false_x_vector(
-; CHECK-NEXT:    [[OR:%.*]] = select <2 x i1> [[Y:%.*]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[X:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = select <2 x i1> [[OR]], <2 x i1> zeroinitializer, <2 x i1> [[X]]
-; CHECK-NEXT:    ret <2 x i1> [[R]]
+; CHECK-NEXT:    ret <2 x i1> zeroinitializer
 ;
   %or = select <2 x i1> %y, <2 x i1> <i1 true, i1 true>, <2 x i1> %x
   %r = select <2 x i1> %or, <2 x i1> <i1 false, i1 false>, <2 x i1> %x
Index: llvm/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/lib/Analysis/InstructionSimplify.cpp
+++ llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4555,9 +4555,16 @@
     if (match(TrueVal, m_One()) && match(FalseVal, m_ZeroInt()))
       return Cond;
 
-    // (X || Y) && (X || !Y) --> X (commuted 8 ways)
     Value *X, *Y;
+    if (match(Cond, m_LogicalOr(m_Value(X), m_Value(Y)))) {
+      auto *C = dyn_cast<Constant>(TrueVal);
+      // (X || Y) ? false : X --> false (commuted 2 ways)
+      if (C && C->isNullValue() && (X == FalseVal || Y == FalseVal))
+        return TrueVal;
+    }
+
     if (match(FalseVal, m_ZeroInt())) {
+      // (X || Y) && (X || !Y) --> X (commuted 8 ways)
       if (match(Cond, m_c_LogicalOr(m_Value(X), m_Not(m_Value(Y)))) &&
           match(TrueVal, m_c_LogicalOr(m_Specific(X), m_Specific(Y))))
         return X;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D138700.478310.patch
Type: text/x-patch
Size: 3790 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20221128/038cf600/attachment.bin>