Makefile.in (dojump.o): Depend on $(GGC_H) and dojump.h.

	* Makefile.in (dojump.o): Depend on $(GGC_H) and dojump.h.
	(GTFILES): Add $(srcdir)/dojump.h.
	(gt-dojump.h): New dependency.
	* dojump.c (and_reg, and_test, shift_test): New static variables.
	(prefer_and_bit_test): New function.
	(do_jump): Use it to choose between (X & (1 << C)) and (X >> C) & 1.

From-SVN: r79732

gcc/ChangeLog

+2004-03-20  Richard Sandiford  <rsandifo@redhat.com>
+
+	* Makefile.in (dojump.o): Depend on $(GGC_H) and dojump.h.
+	(GTFILES): Add $(srcdir)/dojump.h.
+	(gt-dojump.h): New dependency.
+	* dojump.c (and_reg, and_test, shift_test): New static variables.
+	(prefer_and_bit_test): New function.
+	(do_jump): Use it to choose between (X & (1 << C)) and (X >> C) & 1.
+
 2004-03-20  Kazu Hirata  <kazu@cs.umass.edu>
 
 	* c-common.c, cfgcleanup.c, cgraphunit.c, c-pretty-print.c,

gcc/Makefile.in

@@ -1597,7 +1597,7 @@ expr.o : expr.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(TREE_H) f
    except.h reload.h $(GGC_H) langhooks.h intl.h $(TM_P_H) real.h $(TARGET_H)
 dojump.o : dojump.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(TREE_H) \
    flags.h function.h $(EXPR_H) $(OPTABS_H) $(INSN_ATTR_H) insn-config.h \
-   langhooks.h
+   langhooks.h $(GGC_H) gt-dojump.h
 builtins.o : builtins.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(TREE_H)\
    flags.h $(TARGET_H) function.h $(REGS_H) $(EXPR_H) $(OPTABS_H) insn-config.h \
    $(RECOG_H) output.h typeclass.h hard-reg-set.h toplev.h hard-reg-set.h \
@@ -2086,6 +2086,7 @@ GTFILES = $(srcdir)/input.h $(srcdir)/coretypes.h $(srcdir)/cpplib.h \
   $(srcdir)/c-common.h $(srcdir)/c-tree.h \
   $(srcdir)/alias.c $(srcdir)/bitmap.c $(srcdir)/cselib.c $(srcdir)/cgraph.c \
   $(srcdir)/dbxout.c $(srcdir)/dwarf2out.c $(srcdir)/dwarf2asm.c \
+  $(srcdir)/dojump.c \
   $(srcdir)/emit-rtl.c $(srcdir)/except.c $(srcdir)/explow.c $(srcdir)/expr.c \
   $(srcdir)/fold-const.c $(srcdir)/function.c \
   $(srcdir)/gcse.c $(srcdir)/integrate.c $(srcdir)/lists.c $(srcdir)/optabs.c \
@@ -2105,7 +2106,7 @@ gt-cgraph.h gt-coverage.h gtype-desc.h gtype-desc.c gt-except.h \
 gt-function.h gt-integrate.h gt-stmt.h gt-tree.h gt-varasm.h \
 gt-emit-rtl.h gt-explow.h gt-stor-layout.h gt-regclass.h \
 gt-lists.h gt-alias.h gt-cselib.h gt-fold-const.h gt-gcse.h \
-gt-expr.h gt-sdbout.h gt-optabs.h gt-bitmap.h \
+gt-expr.h gt-sdbout.h gt-optabs.h gt-bitmap.h gt-dojump.h \
 gt-dwarf2out.h gt-ra-build.h gt-reg-stack.h gt-dwarf2asm.h \
 gt-dbxout.h gt-c-common.h gt-c-decl.h gt-c-parse.h \
 gt-c-pragma.h gtype-c.h gt-input.h gt-cfglayout.h \

gcc/dojump.c

@@ -33,7 +33,9 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #include "expr.h"
 #include "optabs.h"
 #include "langhooks.h"
+#include "ggc.h"
 
+static bool prefer_and_bit_test (enum machine_mode, int);
 static void do_jump_by_parts_greater (tree, int, rtx, rtx);
 static void do_jump_by_parts_equality (tree, rtx, rtx);
 static void do_compare_and_jump	(tree, enum rtx_code, enum rtx_code, rtx,
@@ -101,6 +103,45 @@ jumpif (tree exp, rtx label)
   do_jump (exp, NULL_RTX, label);
 }
 
+/* Used internally by prefer_and_bit_test.  */
+
+static GTY(()) rtx and_reg;
+static GTY(()) rtx and_test;
+static GTY(()) rtx shift_test;
+
+/* Compare the relative costs of "(X & (1 << BITNUM))" and "(X >> BITNUM) & 1",
+   where X is an arbitrary register of mode MODE.  Return true if the former
+   is preferred.  */
+
+static bool
+prefer_and_bit_test (enum machine_mode mode, int bitnum)
+{
+  if (and_test == 0)
+    {
+      /* Set up rtxes for the two variations.  Use NULL as a placeholder
+	 for the BITNUM-based constants.  */
+      and_reg = gen_rtx_REG (mode, FIRST_PSEUDO_REGISTER);
+      and_test = gen_rtx_AND (mode, and_reg, NULL);
+      shift_test = gen_rtx_AND (mode, gen_rtx_ASHIFTRT (mode, and_reg, NULL),
+				const1_rtx);
+    }
+  else
+    {
+      /* Change the mode of the previously-created rtxes.  */
+      PUT_MODE (and_reg, mode);
+      PUT_MODE (and_test, mode);
+      PUT_MODE (shift_test, mode);
+      PUT_MODE (XEXP (shift_test, 0), mode);
+    }
+
+  /* Fill in the integers.  */
+  XEXP (and_test, 0) = GEN_INT ((unsigned HOST_WIDE_INT) 1 << bitnum);
+  XEXP (XEXP (shift_test, 0), 1) = GEN_INT (bitnum);
+
+  return (rtx_cost (and_test, IF_THEN_ELSE)
+	  <= rtx_cost (shift_test, IF_THEN_ELSE));
+}
+
 /* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if
    the result is zero, or IF_TRUE_LABEL if the result is one.
    Either of IF_FALSE_LABEL and IF_TRUE_LABEL may be zero,
@@ -206,6 +247,29 @@ do_jump (tree exp, rtx if_false_label, rtx if_true_label)
       break;
 
     case BIT_AND_EXPR:
+      /* fold_single_bit_test() converts (X & (1 << C)) into (X >> C) & 1.
+	 See if the former is preferred for jump tests and restore it
+	 if so.  */
+      if (TREE_CODE (TREE_OPERAND (exp, 0)) == RSHIFT_EXPR
+	  && integer_onep (TREE_OPERAND (exp, 1)))
+	{
+	  tree arg = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
+	  tree shift = TREE_OPERAND (TREE_OPERAND (exp, 0), 1);
+	  tree one = TREE_OPERAND (exp, 1);
+	  tree argtype = TREE_TYPE (arg);
+	  if (TREE_CODE (shift) == INTEGER_CST
+	      && compare_tree_int (shift, 0) > 0
+	      && compare_tree_int (shift, HOST_BITS_PER_WIDE_INT) < 0
+	      && prefer_and_bit_test (TYPE_MODE (argtype),
+				      TREE_INT_CST_LOW (shift)))
+	    {
+	      do_jump (build (BIT_AND_EXPR, argtype, arg,
+			      fold (build (LSHIFT_EXPR, argtype, one, shift))),
+		       if_false_label, if_true_label);
+	      break;
+	    }
+	}
+
       /* If we are AND'ing with a small constant, do this comparison in the
          smallest type that fits.  If the machine doesn't have comparisons
          that small, it will be converted back to the wider comparison.
@@ -999,3 +1063,5 @@ do_compare_and_jump (tree exp, enum rtx_code signed_code,
                             ? expr_size (TREE_OPERAND (exp, 0)) : NULL_RTX),
                            if_false_label, if_true_label);
 }
+
+#include "gt-dojump.h"