[llvm-commits] [llvm] r45169 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll

[Christopher Lamb]

Author: clamb
Date: Tue Dec 18 14:30:28 2007
New Revision: 45169

URL: http://llvm.org/viewvc/llvm-project?rev=45169&view=rev
Log:
Remove an orthogonal transformation of the selection condition from my most recent submission.

Modified:
    llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
    llvm/trunk/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll

Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=45169&r1=45168&r2=45169&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Tue Dec 18 14:30:28 2007
@@ -2131,9 +2131,6 @@
     }
   }
   
-  // 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 @@
       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 @@
           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);
       }
     }
   }

Modified: llvm/trunk/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll?rev=45169&r1=45168&r2=45169&view=diff

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/2007-12-18-AddSelCmpSub.ll Tue Dec 18 14:30:28 2007
@@ -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 @@
         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]