[Valgrind-developers] vex: r1956 - trunk/priv

[<sv...@va...>]

Author: sewardj
Date: 2010-01-15 09:54:55 +0000 (Fri, 15 Jan 2010)
New Revision: 1956

Log:
amd64: add a couple more spec cases: NLE after SUBL, and NZ after LOGICB.
x86: add commented out (ATC) spec case for C flag after SMULL.


Modified:
   trunk/priv/guest_amd64_helpers.c
   trunk/priv/guest_x86_helpers.c


Modified: trunk/priv/guest_amd64_helpers.c
===================================================================
--- trunk/priv/guest_amd64_helpers.c	2010-01-11 10:46:18 UTC (rev 1955)
+++ trunk/priv/guest_amd64_helpers.c	2010-01-15 09:54:55 UTC (rev 1956)
@@ -995,7 +995,18 @@
                            binop(Iop_Shl64,cc_dep2,mkU8(32))));
 
       }
+      if (isU64(cc_op, AMD64G_CC_OP_SUBL) && isU64(cond, AMD64CondNLE)) {
+         /* long sub/cmp, then NLE (signed greater than) 
+            --> test !(dst <=s src)
+            --> test (dst >s src)
+            --> test (src <s dst) */
+         return unop(Iop_1Uto64,
+                     binop(Iop_CmpLT64S,
+                           binop(Iop_Shl64,cc_dep2,mkU8(32)),
+                           binop(Iop_Shl64,cc_dep1,mkU8(32))));
 
+      }
+
       if (isU64(cc_op, AMD64G_CC_OP_SUBL) && isU64(cond, AMD64CondBE)) {
          /* long sub/cmp, then BE (unsigned less than or equal)
             --> test dst <=u src */
@@ -1155,6 +1166,12 @@
                      binop(Iop_CmpEQ64, binop(Iop_And64,cc_dep1,mkU64(255)), 
                                         mkU64(0)));
       }
+      if (isU64(cc_op, AMD64G_CC_OP_LOGICB) && isU64(cond, AMD64CondNZ)) {
+         /* byte and/or/xor, then NZ --> test dst!=0 */
+         return unop(Iop_1Uto64,
+                     binop(Iop_CmpNE64, binop(Iop_And64,cc_dep1,mkU64(255)), 
+                                        mkU64(0)));
+      }
 
       if (isU64(cc_op, AMD64G_CC_OP_LOGICB) && isU64(cond, AMD64CondS)) {
          /* this is an idiom gcc sometimes uses to find out if the top

Modified: trunk/priv/guest_x86_helpers.c
===================================================================
--- trunk/priv/guest_x86_helpers.c	2010-01-11 10:46:18 UTC (rev 1955)
+++ trunk/priv/guest_x86_helpers.c	2010-01-15 09:54:55 UTC (rev 1956)
@@ -1272,6 +1272,22 @@
                            binop(Iop_Add32, cc_dep1, cc_dep2), 
                            cc_dep1));
       }
+      // ATC, requires verification, no test case known
+      //if (isU32(cc_op, X86G_CC_OP_SMULL)) {
+      //   /* C after signed widening multiply denotes the case where
+      //      the top half of the result isn't simply the sign extension
+      //      of the bottom half (iow the result doesn't fit completely
+      //      in the bottom half).  Hence: 
+      //        C = hi-half(dep1 x dep2) != lo-half(dep1 x dep2) >>s 31 
+      //      where 'x' denotes signed widening multiply.*/
+      //   return 
+      //      unop(Iop_1Uto32,
+      //           binop(Iop_CmpNE32, 
+      //                 unop(Iop_64HIto32,
+      //                      binop(Iop_MullS32, cc_dep1, cc_dep2)),
+      //                 binop(Iop_Sar32,
+      //                       binop(Iop_Mul32, cc_dep1, cc_dep2), mkU8(31)) ));
+      //}
 #     if 0
       if (cc_op->tag == Iex_Const) {
          vex_printf("CFLAG "); ppIRExpr(cc_op); vex_printf("\n");