Micro optimisation of the day: Remove ia32_Test, which tests the high result of ia32_Mul.

[r22480]

diff --git a/ir/be/ia32/ia32_optimize.c b/ir/be/ia32/ia32_optimize.c
index fdbd566..3ab990f 100644 (file)
--- a/ir/be/ia32/ia32_optimize.c
+++ b/ir/be/ia32/ia32_optimize.c
@@ -72,68 +72,74 @@ static void copy_mark(const ir_node *old, ir_node *new)
                set_ia32_is_remat(new);
 }
 
+typedef enum produces_flag_t {
+       produces_no_flag,
+       produces_flag_zero,
+       produces_flag_carry
+} produces_flag_t;
+
 /**
- * Returns non-zero if the given node produces
- * a zero flag.
+ * Return which usable flag the given node produces
  *
  * @param node  the node to check
- * @param pn    if >= 0, the projection number of the used result
+ * @param pn    the projection number of the used result
  */
-static int produces_zero_flag(ir_node *node, int pn)
+static produces_flag_t produces_test_flag(ir_node *node, int pn)
 {
        ir_node                     *count;
        const ia32_immediate_attr_t *imm_attr;
 
        if (!is_ia32_irn(node))
-               return 0;
-
-       if (pn >= 0) {
-               if (pn != pn_ia32_res)
-                       return 0;
-       }
+               return produces_no_flag;
 
        switch (get_ia32_irn_opcode(node)) {
-       case iro_ia32_Add:
-       case iro_ia32_Adc:
-       case iro_ia32_And:
-       case iro_ia32_Or:
-       case iro_ia32_Xor:
-       case iro_ia32_Sub:
-       case iro_ia32_Sbb:
-       case iro_ia32_Neg:
-       case iro_ia32_Inc:
-       case iro_ia32_Dec:
-               return 1;
-
-       case iro_ia32_ShlD:
-       case iro_ia32_ShrD:
-               assert(n_ia32_ShlD_count == n_ia32_ShrD_count);
-               count = get_irn_n(node, n_ia32_ShlD_count);
-               goto check_shift_amount;
-
-       case iro_ia32_Shl:
-       case iro_ia32_Shr:
-       case iro_ia32_Sar:
-               assert(n_ia32_Shl_count == n_ia32_Shr_count
-                               && n_ia32_Shl_count == n_ia32_Sar_count);
-               count = get_irn_n(node, n_ia32_Shl_count);
+               case iro_ia32_Add:
+               case iro_ia32_Adc:
+               case iro_ia32_And:
+               case iro_ia32_Or:
+               case iro_ia32_Xor:
+               case iro_ia32_Sub:
+               case iro_ia32_Sbb:
+               case iro_ia32_Neg:
+               case iro_ia32_Inc:
+               case iro_ia32_Dec:
+                       break;
+
+               case iro_ia32_ShlD:
+               case iro_ia32_ShrD:
+                       assert(n_ia32_ShlD_count == n_ia32_ShrD_count);
+                       count = get_irn_n(node, n_ia32_ShlD_count);
+                       goto check_shift_amount;
+
+               case iro_ia32_Shl:
+               case iro_ia32_Shr:
+               case iro_ia32_Sar:
+                       assert(n_ia32_Shl_count == n_ia32_Shr_count
+                                       && n_ia32_Shl_count == n_ia32_Sar_count);
+                       count = get_irn_n(node, n_ia32_Shl_count);
 check_shift_amount:
-               /* when shift count is zero the flags are not affected, so we can only
-                * do this for constants != 0 */
-               if (!is_ia32_Immediate(count))
-                       return 0;
-
-               imm_attr = get_ia32_immediate_attr_const(count);
-               if (imm_attr->symconst != NULL)
-                       return 0;
-               if ((imm_attr->offset & 0x1f) == 0)
-                       return 0;
-               return 1;
-
-       default:
-               break;
+                       /* when shift count is zero the flags are not affected, so we can only
+                        * do this for constants != 0 */
+                       if (!is_ia32_Immediate(count))
+                               return produces_no_flag;
+
+                       imm_attr = get_ia32_immediate_attr_const(count);
+                       if (imm_attr->symconst != NULL)
+                               return produces_no_flag;
+                       if ((imm_attr->offset & 0x1f) == 0)
+                               return produces_no_flag;
+                       break;
+
+               case iro_ia32_Mul:
+                       return pn == pn_ia32_Mul_res_high ?
+                               produces_flag_carry : produces_no_flag;
+
+               default:
+                       return produces_no_flag;
        }
-       return 0;
+
+       return pn == pn_ia32_res ?
+               produces_flag_zero : produces_no_flag;
 }
 
 /**
@@ -248,7 +254,7 @@ static void peephole_ia32_Test(ir_node *node)
        ir_node         *flags_proj;
        ir_node         *block;
        ir_mode         *flags_mode;
-       int              pn    = -1;
+       int              pn    = pn_ia32_res;
        ir_node         *schedpoint;
        const ir_edge_t *edge;
 
@@ -295,8 +301,27 @@ static void peephole_ia32_Test(ir_node *node)
                }
        }
 
-       if(!produces_zero_flag(left, pn))
-               return;
+       switch (produces_test_flag(left, pn)) {
+               case produces_flag_zero:
+                       break;
+
+               case produces_flag_carry:
+                       foreach_out_edge(node, edge) {
+                               ir_node *user = get_edge_src_irn(edge);
+                               int      pnc  = get_ia32_condcode(user);
+
+                               switch (pnc) {
+                                       case pn_Cmp_Eq: pnc = pn_Cmp_Ge | ia32_pn_Cmp_unsigned; break;
+                                       case pn_Cmp_Lg: pnc = pn_Cmp_Lt | ia32_pn_Cmp_unsigned; break;
+                                       default: panic("unexpected pn");
+                               }
+                               set_ia32_condcode(user, pnc);
+                       }
+                       break;
+
+               default:
+                       return;
+       }
 
        left = turn_into_mode_t(left);
 

diff --git a/ir/be/ia32/ia32_spec.pl b/ir/be/ia32/ia32_spec.pl
index b172fd4..f830e75 100644 (file)
--- a/ir/be/ia32/ia32_spec.pl
+++ b/ir/be/ia32/ia32_spec.pl
@@ -434,10 +434,10 @@ Mul => {
        # very strict constraints
        state     => "exc_pinned",
        reg_req   => { in => [ "gp", "gp", "none", "eax", "gp" ],
-                      out => [ "eax", "edx", "none" ] },
+                      out => [ "eax", "flags", "edx", "none" ] },
        ins       => [ "base", "index", "mem", "left", "right" ],
        emit      => '. mul%M %unop4',
-       outs      => [ "res_low", "res_high", "M" ],
+       outs      => [ "res_low", "flags", "res_high", "M" ],
        am        => "source,binary",
        latency   => 10,
        units     => [ "GP" ],
@@ -449,7 +449,7 @@ l_Mul => {
        # very strict constraints
        op_flags  => "C",
        cmp_attr  => "return 1;",
-       outs      => [ "EAX", "EDX", "M" ],
+       outs      => [ "EAX", "flags", "EDX", "M" ],
        arity     => 2
 },