Fix a bug in my load/cast folding patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12849 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 28 insertions, 24 deletions

diff --git a/lib/Target/X86/InstSelectSimple.cpp b/lib/Target/X86/InstSelectSimple.cpp
index 2477da0..a2e7e66 100644
--- a/lib/Target/X86/InstSelectSimple.cpp
+++ b/lib/Target/X86/InstSelectSimple.cpp
@@ -2759,15 +2759,17 @@ void ISel::visitStoreInst(StoreInst &I) {
 void ISel::visitCastInst(CastInst &CI) {
   Value *Op = CI.getOperand(0);
 
-  // Noop casts are not even emitted.
-  if (getClassB(CI.getType()) == getClassB(Op->getType()))
+  unsigned SrcClass = getClassB(Op->getType());
+  unsigned DestClass = getClassB(CI.getType());
+  // Noop casts are not emitted: getReg will return the source operand as the
+  // register to use for any uses of the noop cast.
+  if (DestClass == SrcClass)
     return;
 
   // If this is a cast from a 32-bit integer to a Long type, and the only uses
   // of the case are GEP instructions, then the cast does not need to be
   // generated explicitly, it will be folded into the GEP.
-  if (CI.getType() == Type::LongTy &&
-      (Op->getType() == Type::IntTy || Op->getType() == Type::UIntTy)) {
+  if (DestClass == cLong && SrcClass == cInt) {
     bool AllUsesAreGEPs = true;
     for (Value::use_iterator I = CI.use_begin(), E = CI.use_end(); I != E; ++I)
       if (!isa<GetElementPtrInst>(*I)) {
@@ -2779,6 +2781,14 @@ void ISel::visitCastInst(CastInst &CI) {
     if (AllUsesAreGEPs) return;
   }
 
+  // If this cast converts a load from a short,int, or long integer to a FP
+  // value, we will have folded this cast away.
+  if (DestClass == cFP && isa<LoadInst>(Op) && Op->hasOneUse() &&
+      (Op->getType() == Type::ShortTy || Op->getType() == Type::IntTy ||
+       Op->getType() == Type::LongTy))
+    return;
+
+
   unsigned DestReg = getReg(CI);
   MachineBasicBlock::iterator MI = BB->end();
   emitCastOperation(BB, MI, Op, CI.getType(), DestReg);
@@ -2794,14 +2804,6 @@ void ISel::emitCastOperation(MachineBasicBlock *BB,
   const Type *SrcTy = Src->getType();
   unsigned SrcClass = getClassB(SrcTy);
   unsigned DestClass = getClassB(DestTy);
-
-  // If this cast converts a load from a short,int, or long integer to a FP
-  // value, we will have folded this cast away.
-  if (DestClass == cFP && isa<LoadInst>(Src) &&
-      (Src->getType() == Type::ShortTy || Src->getType() == Type::IntTy ||
-       Src->getType() == Type::LongTy))
-    return;
-
   unsigned SrcReg = getReg(Src, BB, IP);
 
   // Implement casts to bool by using compare on the operand followed by set if
diff --git a/lib/Target/X86/X86ISelSimple.cpp b/lib/Target/X86/X86ISelSimple.cpp
index 2477da0..a2e7e66 100644
--- a/lib/Target/X86/X86ISelSimple.cpp
+++ b/lib/Target/X86/X86ISelSimple.cpp
@@ -2759,15 +2759,17 @@ void ISel::visitStoreInst(StoreInst &I) {
 void ISel::visitCastInst(CastInst &CI) {
   Value *Op = CI.getOperand(0);
 
-  // Noop casts are not even emitted.
-  if (getClassB(CI.getType()) == getClassB(Op->getType()))
+  unsigned SrcClass = getClassB(Op->getType());
+  unsigned DestClass = getClassB(CI.getType());
+  // Noop casts are not emitted: getReg will return the source operand as the
+  // register to use for any uses of the noop cast.
+  if (DestClass == SrcClass)
     return;
 
   // If this is a cast from a 32-bit integer to a Long type, and the only uses
   // of the case are GEP instructions, then the cast does not need to be
   // generated explicitly, it will be folded into the GEP.
-  if (CI.getType() == Type::LongTy &&
-      (Op->getType() == Type::IntTy || Op->getType() == Type::UIntTy)) {
+  if (DestClass == cLong && SrcClass == cInt) {
     bool AllUsesAreGEPs = true;
     for (Value::use_iterator I = CI.use_begin(), E = CI.use_end(); I != E; ++I)
       if (!isa<GetElementPtrInst>(*I)) {
@@ -2779,6 +2781,14 @@ void ISel::visitCastInst(CastInst &CI) {
     if (AllUsesAreGEPs) return;
   }
 
+  // If this cast converts a load from a short,int, or long integer to a FP
+  // value, we will have folded this cast away.
+  if (DestClass == cFP && isa<LoadInst>(Op) && Op->hasOneUse() &&
+      (Op->getType() == Type::ShortTy || Op->getType() == Type::IntTy ||
+       Op->getType() == Type::LongTy))
+    return;
+
+
   unsigned DestReg = getReg(CI);
   MachineBasicBlock::iterator MI = BB->end();
   emitCastOperation(BB, MI, Op, CI.getType(), DestReg);
@@ -2794,14 +2804,6 @@ void ISel::emitCastOperation(MachineBasicBlock *BB,
   const Type *SrcTy = Src->getType();
   unsigned SrcClass = getClassB(SrcTy);
   unsigned DestClass = getClassB(DestTy);
-
-  // If this cast converts a load from a short,int, or long integer to a FP
-  // value, we will have folded this cast away.
-  if (DestClass == cFP && isa<LoadInst>(Src) &&
-      (Src->getType() == Type::ShortTy || Src->getType() == Type::IntTy ||
-       Src->getType() == Type::LongTy))
-    return;
-
   unsigned SrcReg = getReg(Src, BB, IP);
 
   // Implement casts to bool by using compare on the operand followed by set if