[llvm-commits] [llvm] r156849 - /llvm/trunk/lib/Analysis/ScalarEvolution.cpp

[Nuno Lopes]

Author: nlopes
Date: Tue May 15 15:20:14 2012
New Revision: 156849

URL: http://llvm.org/viewvc/llvm-project?rev=156849&view=rev
Log:
reuse the result of some expensive computations in getSignExtendExpr() and getZeroExtendExpr()
this gives a speedup of > 80 in a debug build in the test case of PR12825 (php_sha512_crypt_r)

Modified:
    llvm/trunk/lib/Analysis/ScalarEvolution.cpp

Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=156849&r1=156848&r2=156849&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Tue May 15 15:20:14 2012
@@ -974,12 +974,15 @@
           Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
           // Check whether Start+Step*MaxBECount has no unsigned overflow.
           const SCEV *ZMul = getMulExpr(CastedMaxBECount, Step);
-          const SCEV *Add = getAddExpr(Start, ZMul);
+          const SCEV *ZAdd = getZeroExtendExpr(getAddExpr(Start, ZMul), WideTy);
+          const SCEV *WideStart = getZeroExtendExpr(Start, WideTy);
+          const SCEV *WideMaxBECount =
+            getZeroExtendExpr(CastedMaxBECount, WideTy);
           const SCEV *OperandExtendedAdd =
-            getAddExpr(getZeroExtendExpr(Start, WideTy),
-                       getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
+            getAddExpr(WideStart,
+                       getMulExpr(WideMaxBECount,
                                   getZeroExtendExpr(Step, WideTy)));
-          if (getZeroExtendExpr(Add, WideTy) == OperandExtendedAdd) {
+          if (ZAdd == OperandExtendedAdd) {
             // Cache knowledge of AR NUW, which is propagated to this AddRec.
             const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNUW);
             // Return the expression with the addrec on the outside.
@@ -989,13 +992,11 @@
           }
           // Similar to above, only this time treat the step value as signed.
           // This covers loops that count down.
-          const SCEV *SMul = getMulExpr(CastedMaxBECount, Step);
-          Add = getAddExpr(Start, SMul);
           OperandExtendedAdd =
-            getAddExpr(getZeroExtendExpr(Start, WideTy),
-                       getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
+            getAddExpr(WideStart,
+                       getMulExpr(WideMaxBECount,
                                   getSignExtendExpr(Step, WideTy)));
-          if (getZeroExtendExpr(Add, WideTy) == OperandExtendedAdd) {
+          if (ZAdd == OperandExtendedAdd) {
             // Cache knowledge of AR NW, which is propagated to this AddRec.
             // Negative step causes unsigned wrap, but it still can't self-wrap.
             const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNW);
@@ -1239,12 +1240,15 @@
           Type *WideTy = IntegerType::get(getContext(), BitWidth * 2);
           // Check whether Start+Step*MaxBECount has no signed overflow.
           const SCEV *SMul = getMulExpr(CastedMaxBECount, Step);
-          const SCEV *Add = getAddExpr(Start, SMul);
+          const SCEV *SAdd = getSignExtendExpr(getAddExpr(Start, SMul), WideTy);
+          const SCEV *WideStart = getSignExtendExpr(Start, WideTy);
+          const SCEV *WideMaxBECount =
+            getZeroExtendExpr(CastedMaxBECount, WideTy);
           const SCEV *OperandExtendedAdd =
-            getAddExpr(getSignExtendExpr(Start, WideTy),
-                       getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
+            getAddExpr(WideStart,
+                       getMulExpr(WideMaxBECount,
                                   getSignExtendExpr(Step, WideTy)));
-          if (getSignExtendExpr(Add, WideTy) == OperandExtendedAdd) {
+          if (SAdd == OperandExtendedAdd) {
             // Cache knowledge of AR NSW, which is propagated to this AddRec.
             const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
             // Return the expression with the addrec on the outside.
@@ -1254,13 +1258,11 @@
           }
           // Similar to above, only this time treat the step value as unsigned.
           // This covers loops that count up with an unsigned step.
-          const SCEV *UMul = getMulExpr(CastedMaxBECount, Step);
-          Add = getAddExpr(Start, UMul);
           OperandExtendedAdd =
-            getAddExpr(getSignExtendExpr(Start, WideTy),
-                       getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
+            getAddExpr(WideStart,
+                       getMulExpr(WideMaxBECount,
                                   getZeroExtendExpr(Step, WideTy)));
-          if (getSignExtendExpr(Add, WideTy) == OperandExtendedAdd) {
+          if (SAdd == OperandExtendedAdd) {
             // Cache knowledge of AR NSW, which is propagated to this AddRec.
             const_cast<SCEVAddRecExpr *>(AR)->setNoWrapFlags(SCEV::FlagNSW);
             // Return the expression with the addrec on the outside.