From a562b2018aa7ee365be762916ca88c26b81d62dd Mon Sep 17 00:00:00 2001
From: borutr <borutr@4a8a32a2-be11-0410-ad9d-d568d2c75423>
Date: Sat, 19 Jan 2008 23:49:32 +0000
Subject: [PATCH] * src/SDCCcse.c: partially fixed enhancement request  
 #1793872 - multiply by -1 not collapsed *
 support/regression/tests/arithcsi.c: added regression test

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@4996 4a8a32a2-be11-0410-ad9d-d568d2c75423
---
 ChangeLog     |  6 ++++++
 src/SDCCcse.c | 25 +++++++++++++++++++++----
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b973a16b..3c846a25 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2008-01-20 Borut Razem <borut.razem AT siol.net>
+
+	* src/SDCCcse.c: partially fixed enhancement request
+	  #1793872 - multiply by -1 not collapsed
+	* support/regression/tests/arithcsi.c: added regression test
+
 2008-01-19 Maarten Brock <sourceforge.brock AT dse.nl>
 
 	* as/mcs51/asx8051.dsp: removed define SDK
diff --git a/src/SDCCcse.c b/src/SDCCcse.c
index fc45babf..f6e6ec03 100644
--- a/src/SDCCcse.c
+++ b/src/SDCCcse.c
@@ -957,8 +957,9 @@ algebraicOpts (iCode * ic, eBBlock * ebp)
     case '*':
       if (IS_OP_LITERAL (IC_LEFT (ic)))
         {
+         double leftValue = operandLitValue (IC_LEFT (ic));
 
-          if (operandLitValue (IC_LEFT (ic)) == 0.0)
+          if (leftValue == 0.0)
             {
               ic->op = '=';
               IC_RIGHT (ic) = IC_LEFT (ic);
@@ -966,7 +967,7 @@ algebraicOpts (iCode * ic, eBBlock * ebp)
               SET_RESULT_RIGHT (ic);
               return;
             }
-          if (operandLitValue (IC_LEFT (ic)) == 1.0)
+          if (leftValue == 1.0)
             {
               /* '*' can have two unsigned chars as operands */
               /* and an unsigned int as result.              */
@@ -987,12 +988,21 @@ algebraicOpts (iCode * ic, eBBlock * ebp)
                 }
               return;
             }
+          if (leftValue == -1.0)
+            {
+              /* convert -1 * x to -x */
+              ic->op = UNARYMINUS;
+              IC_LEFT (ic) = IC_RIGHT (ic);
+              IC_RIGHT (ic) = NULL;
+              return;
+            }
         }
 
       if (IS_OP_LITERAL (IC_RIGHT (ic)))
         {
+          double rightValue = operandLitValue (IC_RIGHT (ic));
 
-          if (operandLitValue (IC_RIGHT (ic)) == 0.0)
+          if (rightValue == 0.0)
             {
               ic->op = '=';
               IC_LEFT (ic) = NULL;
@@ -1000,7 +1010,7 @@ algebraicOpts (iCode * ic, eBBlock * ebp)
               return;
             }
 
-          if (operandLitValue (IC_RIGHT (ic)) == 1.0)
+          if (rightValue == 1.0)
             {
               /* '*' can have two unsigned chars as operands */
               /* and an unsigned int as result.              */
@@ -1026,6 +1036,13 @@ algebraicOpts (iCode * ic, eBBlock * ebp)
                 }
               return;
             }
+          if (rightValue == -1.0)
+            {
+              /* convert x * -1 to -x */
+              ic->op = UNARYMINUS;
+              IC_RIGHT (ic) = NULL;
+              return;
+            }
         }
       break;
     case '/':
-- 
2.30.2