From 92b969ba80a6ed6d461c5e874db259f8c0a95290 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Tue, 14 Jul 2009 20:57:04 +0000
Subject: 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
---
 llvm/lib/Analysis/ScalarEvolutionExpander.cpp | 32 ++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 6 deletions(-)

(limited to 'llvm/lib/Analysis/ScalarEvolutionExpander.cpp')

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;
 }
 
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