From: Julian Seward <jseward@acm.org>
Date: Sat, 22 Jan 2005 11:00:42 +0000 (+0000)
Subject: Another speedup case resulting from profiled runs of bzip2.
X-Git-Tag: svn/VALGRIND_3_0_1^2~596
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=8f63b956be6d8782879715f156fee599151e3cdc;p=thirdparty%2Fvalgrind.git

Another speedup case resulting from profiled runs of bzip2.


git-svn-id: svn://svn.valgrind.org/vex/trunk@738
---

diff --git a/VEX/priv/guest-x86/ghelpers.c b/VEX/priv/guest-x86/ghelpers.c
index e983cbad4e..6e1b746ff0 100644
--- a/VEX/priv/guest-x86/ghelpers.c
+++ b/VEX/priv/guest-x86/ghelpers.c
@@ -544,14 +544,14 @@ UInt x86g_calculate_eflags_c ( UInt cc_op,
       case X86G_CC_OP_SUBL:
          return ((UInt)cc_dep1) < ((UInt)cc_dep2)
                    ? X86G_CC_MASK_C : 0;
-#if 0
       case X86G_CC_OP_SUBB:
          return ((UInt)(cc_dep1 & 0xFF)) < ((UInt)(cc_dep2 & 0xFF))
                    ? X86G_CC_MASK_C : 0;
-#endif
-#if 0
+      case X86G_CC_OP_INCL:
       case X86G_CC_OP_DECL:
-         return cc_src;
+         return cc_ndep & X86G_CC_MASK_C;
+#if 0
+      /* unclear if these are correct or not */
       case X86G_CC_OP_ADDL:
          return ( ((UInt)cc_src + (UInt)cc_dst) < ((UInt)cc_src) ) 
                    ? X86G_CC_MASK_C : 0;
@@ -703,6 +703,13 @@ IRExpr* guest_x86_spechelper ( Char* function_name,
          return unop(Iop_1Uto32,
                      binop(Iop_CmpLT32U, cc_dep1, cc_dep2));
       }
+      if (isU32(cc_op, X86G_CC_OP_SUBB)) {
+         /* C after sub denotes unsigned less than */
+         return unop(Iop_1Uto32,
+                     binop(Iop_CmpLT32U, 
+                           binop(Iop_And32,cc_dep1,mkU32(0xFF)),
+                           binop(Iop_And32,cc_dep2,mkU32(0xFF))));
+      }
       if (isU32(cc_op, X86G_CC_OP_LOGICL)) {
          /* cflag after logic is zero */
          return mkU32(0);