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[Valgrind-developers] vex: r1818 - in
branches/OTRACK_BY_INSTRUMENTATION/priv: guest-amd64 guest-x86
From: <sv...@va...> - 2008-04-01 11:05:20
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Author: sewardj
Date: 2008-04-01 12:05:00 +0100 (Tue, 01 Apr 2008)
New Revision: 1818
Log:
Merge (from trunk) r1816,r1817: specialise CondNS after SUBB on x86,amd64.
Modified:
branches/OTRACK_BY_INSTRUMENTATION/priv/guest-amd64/ghelpers.c
branches/OTRACK_BY_INSTRUMENTATION/priv/guest-x86/ghelpers.c
Modified: branches/OTRACK_BY_INSTRUMENTATION/priv/guest-amd64/ghelpers.c
===================================================================
--- branches/OTRACK_BY_INSTRUMENTATION/priv/guest-amd64/ghelpers.c 2008-03-31 21:57:17 UTC (rev 1817)
+++ branches/OTRACK_BY_INSTRUMENTATION/priv/guest-amd64/ghelpers.c 2008-04-01 11:05:00 UTC (rev 1818)
@@ -1043,6 +1043,18 @@
binop(Iop_Shr64,cc_dep1,mkU8(7)),
mkU64(1));
}
+ if (isU64(cc_op, AMD64G_CC_OP_SUBB) && isU64(cond, AMD64CondNS)
+ && isU64(cc_dep2, 0)) {
+ /* byte sub/cmp of zero, then NS --> test !(dst-0 <s 0)
+ --> test !(dst <s 0)
+ --> (ULong) !dst[7]
+ */
+ return binop(Iop_Xor64,
+ binop(Iop_And64,
+ binop(Iop_Shr64,cc_dep1,mkU8(7)),
+ mkU64(1)),
+ mkU64(1));
+ }
/*---------------- LOGICQ ----------------*/
Modified: branches/OTRACK_BY_INSTRUMENTATION/priv/guest-x86/ghelpers.c
===================================================================
--- branches/OTRACK_BY_INSTRUMENTATION/priv/guest-x86/ghelpers.c 2008-03-31 21:57:17 UTC (rev 1817)
+++ branches/OTRACK_BY_INSTRUMENTATION/priv/guest-x86/ghelpers.c 2008-04-01 11:05:00 UTC (rev 1818)
@@ -967,6 +967,18 @@
binop(Iop_Shr32,cc_dep1,mkU8(7)),
mkU32(1));
}
+ if (isU32(cc_op, X86G_CC_OP_SUBB) && isU32(cond, X86CondNS)
+ && isU32(cc_dep2, 0)) {
+ /* byte sub/cmp of zero, then NS --> test !(dst-0 <s 0)
+ --> test !(dst <s 0)
+ --> (UInt) !dst[7]
+ */
+ return binop(Iop_Xor32,
+ binop(Iop_And32,
+ binop(Iop_Shr32,cc_dep1,mkU8(7)),
+ mkU32(1)),
+ mkU32(1));
+ }
/*---------------- LOGICL ----------------*/
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