Remove an orthogonal transformation of the selection condition from my most recent...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45169 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index d64afbbda1f635ec24ab946e0f4f6f9a20b10cf2..dec298b14b1b75fb6541eeac184d9ee17c17e05e 100644 (file)
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -2131,9 +2131,6 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
     }
   }
   
-  // add (select (icmp 0 (sub m A)) X Y) A ->
-  //   add (select (icmp A m) X Y) A
-  // 
   // add (select X 0 (sub n A)) A ->
   //  select X A n
   {
@@ -2147,27 +2144,6 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
       Value *TV = SI->getTrueValue();
       Value *FV = SI->getFalseValue();
       Value *A;
-            
-      // Can we fold the add into the argument of the compare?
-      Value *Cond = SI->getCondition();
-      if (ICmpInst *IC = dyn_cast<ICmpInst>(Cond)) {
-        Value *ICOp0 = IC->getOperand(0);
-        Value *ICOp1 = IC->getOperand(1);
-        ConstantInt *C3, *C4;
-        
-        // Check both arguments of the compare for a matching subtract.
-        if (match(ICOp0, m_ConstantInt(C3)) && C3->getValue() == 0 &&
-            match(ICOp1, m_Sub(m_ConstantInt(C4), m_Value(A))) &&
-            A == Other) {
-          // We managed to fold the add into the RHS of the select condition.
-          Cond = new ICmpInst(IC->getPredicate(), A, C4, "asis", SI);
-        } else if (match(ICOp1, m_ConstantInt(C3)) && C3->getValue() == 0 &&
-            match(ICOp0, m_Sub(m_ConstantInt(C4), m_Value(A))) &&
-            A == Other) {
-          // We managed to fold the add into the LHS of the select condition.
-          Cond = new ICmpInst(IC->getPredicate(), C4, A, "asis", SI);
-        }
-      }
 
       // Can we fold the add into the argument of the select?
       // We check both true and false select arguments for a matching subtract.
@@ -2177,17 +2153,13 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
           A == Other) {
         // We managed to fold the add into the true select value,
         // picking up a simplified condition, if available.
-        return new SelectInst(Cond, C2, A, "adselsub");
+        return new SelectInst(SI->getCondition(), C2, A);
       } else if (match(TV, m_ConstantInt(C1)) && C1->getValue() == 0 && 
                  match(FV, m_Sub(m_ConstantInt(C2), m_Value(A))) &&
                  A == Other) {
         // We managed to fold the add into the false select value,
         // picking up a simplified condition, if available.
-        return new SelectInst(Cond, A, C2, "adselsub");
-      } else if (Cond != SI->getCondition()) {
-        // We only managed to fold the add into the select condition.
-        SI->setOperand(0, Cond);
-        Changed = true;
+        return new SelectInst(SI->getCondition(), A, C2);
       }
     }
   }

diff --git a/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll b/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll
index 94d6c9689206c47dd1e5bf145d2f0822e6384552..e44fc6f099a76e76a3ea1c5c944c4b2f6ae6fd7d 100644 (file)
--- a/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll
+++ b/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll
@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep {sub}
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {add} | count 1
 
 define i32 @foo(i32 %a) {
 entry:
@@ -19,15 +19,6 @@ entry:
         ret i32 %tmp12
 }
 
-define i32 @baz(i32 %a) {
-entry:
-        %tmp15 = sub i32 99, %a         ; <i32> [#uses=1]
-        %tmp16 = icmp slt i32 %tmp15, 0         ; <i1> [#uses=1]
-        %smax = select i1 %tmp16, i32 0, i32 42             ; <i32> [#uses=1]
-        %tmp12 = add i32 %smax, %a              ; <i32> [#uses=1]
-        ret i32 %tmp12
-}
-
 define i32 @fun(i32 %a) {
 entry:
         %tmp15 = sub i32 99, %a         ; <i32> [#uses=1]