Fix the expansion of umax and smax in the case where one or more of

the operands have pointer type, so that the resulting type matches
the original SCEV type, and so that unnecessary ptrtoints are
avoided in common cases.

llvm-svn: 75680

1 files changed, 26 insertions, 6 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
index ecfbc8ec79f..20d6e20601f 100644
--- a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -609,9 +609,15 @@ Value *SCEVExpander::visitSignExtendExpr(const SCEVSignExtendExpr *S) {
 }
 
 Value *SCEVExpander::visitSMaxExpr(const SCEVSMaxExpr *S) {
-  const Type *Ty = SE.getEffectiveSCEVType(S->getType());
-  Value *LHS = expandCodeFor(S->getOperand(0), Ty);
-  for (unsigned i = 1; i < S->getNumOperands(); ++i) {
+  Value *LHS = expand(S->getOperand(S->getNumOperands()-1));
+  const Type *Ty = LHS->getType();
+  for (int i = S->getNumOperands()-2; i >= 0; --i) {
+    // In the case of mixed integer and pointer types, do the
+    // rest of the comparisons as integer.
+    if (S->getOperand(i)->getType() != Ty) {
+      Ty = SE.getEffectiveSCEVType(Ty);
+      LHS = InsertNoopCastOfTo(LHS, Ty);
+    }
     Value *RHS = expandCodeFor(S->getOperand(i), Ty);
     Value *ICmp = Builder.CreateICmpSGT(LHS, RHS, "tmp");
     InsertedValues.insert(ICmp);
@@ -619,13 +625,23 @@ Value *SCEVExpander::visitSMaxExpr(const SCEVSMaxExpr *S) {
     InsertedValues.insert(Sel);
     LHS = Sel;
   }
+  // In the case of mixed integer and pointer types, cast the
+  // final result back to the pointer type.
+  if (LHS->getType() != S->getType())
+    LHS = InsertNoopCastOfTo(LHS, S->getType());
   return LHS;
 }
 
 Value *SCEVExpander::visitUMaxExpr(const SCEVUMaxExpr *S) {
-  const Type *Ty = SE.getEffectiveSCEVType(S->getType());
-  Value *LHS = expandCodeFor(S->getOperand(0), Ty);
-  for (unsigned i = 1; i < S->getNumOperands(); ++i) {
+  Value *LHS = expand(S->getOperand(S->getNumOperands()-1));
+  const Type *Ty = LHS->getType();
+  for (int i = S->getNumOperands()-2; i >= 0; --i) {
+    // In the case of mixed integer and pointer types, do the
+    // rest of the comparisons as integer.
+    if (S->getOperand(i)->getType() != Ty) {
+      Ty = SE.getEffectiveSCEVType(Ty);
+      LHS = InsertNoopCastOfTo(LHS, Ty);
+    }
     Value *RHS = expandCodeFor(S->getOperand(i), Ty);
     Value *ICmp = Builder.CreateICmpUGT(LHS, RHS, "tmp");
     InsertedValues.insert(ICmp);
@@ -633,6 +649,10 @@ Value *SCEVExpander::visitUMaxExpr(const SCEVUMaxExpr *S) {
     InsertedValues.insert(Sel);
     LHS = Sel;
   }
+  // In the case of mixed integer and pointer types, cast the
+  // final result back to the pointer type.
+  if (LHS->getType() != S->getType())
+    LHS = InsertNoopCastOfTo(LHS, S->getType());
   return LHS;
 }