From 2ea09e05466613a22e1211f52c30cd01af563983 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Thu, 24 Jun 2010 16:57:52 +0000
Subject: [PATCH] A few minor micro-optimizations.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106764 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/LoopStrengthReduce.cpp | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 94999ad66b3..7d1b7e0d3ab 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -449,6 +449,7 @@ static const SCEV *getExactSDiv(const SCEV *LHS, const SCEV *RHS,
       if (!Step) return 0;
       return SE.getAddRecExpr(Start, Step, AR->getLoop());
     }
+    return 0;
   }
 
   // Distribute the sdiv over add operands, if the add doesn't overflow.
@@ -464,10 +465,11 @@ static const SCEV *getExactSDiv(const SCEV *LHS, const SCEV *RHS,
       }
       return SE.getAddExpr(Ops);
     }
+    return 0;
   }
 
   // Check for a multiply operand that we can pull RHS out of.
-  if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(LHS))
+  if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(LHS)) {
     if (IgnoreSignificantBits || isMulSExtable(Mul, SE)) {
       SmallVector<const SCEV *, 4> Ops;
       bool Found = false;
@@ -484,6 +486,8 @@ static const SCEV *getExactSDiv(const SCEV *LHS, const SCEV *RHS,
       }
       return Found ? SE.getMulExpr(Ops) : 0;
     }
+    return 0;
+  }
 
   // Otherwise we don't know.
   return 0;
@@ -2397,13 +2401,12 @@ void LSRInstance::GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx,
   for (SmallSetVector<int64_t, 8>::const_iterator
        I = Factors.begin(), E = Factors.end(); I != E; ++I) {
     int64_t Factor = *I;
-    Formula F = Base;
 
     // Check that the multiplication doesn't overflow.
-    if (F.AM.BaseOffs == INT64_MIN && Factor == -1)
+    if (Base.AM.BaseOffs == INT64_MIN && Factor == -1)
       continue;
-    F.AM.BaseOffs = (uint64_t)Base.AM.BaseOffs * Factor;
-    if (F.AM.BaseOffs / Factor != Base.AM.BaseOffs)
+    int64_t NewBaseOffs = (uint64_t)Base.AM.BaseOffs * Factor;
+    if (NewBaseOffs / Factor != Base.AM.BaseOffs)
       continue;
 
     // Check that multiplying with the use offset doesn't overflow.
@@ -2414,6 +2417,9 @@ void LSRInstance::GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx,
     if (Offset / Factor != LU.MinOffset)
       continue;
 
+    Formula F = Base;
+    F.AM.BaseOffs = NewBaseOffs;
+
     // Check that this scale is legal.
     if (!isLegalUse(F.AM, Offset, Offset, LU.Kind, LU.AccessTy, TLI))
       continue;