re PR rtl-optimization/3640 (small lost optimization of "x==0 || x==1")

        PR opt/3640
        * fold-const.c (fold): Optimize unsigned comparisons against
        UINT_MAX (and similar unsigned constants).

From-SVN: r49096

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7b966f98a19b6f278e9abfa0067646d60c25a9f8..5cafb331906c77c7502c8289fde6296b4c60e280 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,8 +1,15 @@
+2002-01-22  Roger Sayle  <roger@eyesopen.com>
+           Richard Henderson  <rth@redhat.com>
+
+       PR opt/3640
+       * fold-const.c (fold): Optimize unsigned comparisons against
+       UINT_MAX (and similar unsigned constants).
+
 2002-01-22  Janis Johnson  <janis187@us.ibm.com>
 
-        * Makefile.in (loop.o): Depend on OPTABS_H.
-        * loop.c (expand_builtin_prefetch): Check the prefetch operand
-        against the predicate.
+       * Makefile.in (loop.o): Depend on OPTABS_H.
+       * loop.c (expand_builtin_prefetch): Check the prefetch operand
+       against the predicate.
 
        PR target/5379
        * config/i386/i386.md (prefetch_sse): Specify "p" as a constraint
@@ -25,18 +32,18 @@
 
 2002-01-22  Aldy Hernandez  <aldyh@redhat.com>
 
-        * regrename.c (kill_value): Fix typo.
+       * regrename.c (kill_value): Fix typo.
 
 2002-01-22  Aldy Hernandez  <aldyh@redhat.com>
 
-        * doc/tm.texi: Remove STARTING_FRAME_PHASE.
+       * doc/tm.texi: Remove STARTING_FRAME_PHASE.
 
-        * config/rs6000/rs6000.h: Same.
+       * config/rs6000/rs6000.h: Same.
 
-        * function.c (instantiate_virtual_regs): Remove
-        STARTING_FRAME_PHASE.
-        (assign_stack_local_1): Same.
-        Calculate frame phase.
+       * function.c (instantiate_virtual_regs): Remove
+       STARTING_FRAME_PHASE.
+       (assign_stack_local_1): Same.
+       Calculate frame phase.
 
 2002-01-22  Nick Clifton  <nickc@redhat.com>
 
@@ -276,15 +283,15 @@ Sun Jan 20 18:40:14 2002  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
 
 2002-01-18  Aldy Hernandez  <aldyh@redhat.com>
 
-        * doc/tm.texi (STARTING_FRAME_PHASE): Document.
+       * doc/tm.texi (STARTING_FRAME_PHASE): Document.
 
-        * function.c (assign_stack_local_1): Adjust x_frame_offset with
-        STARTING_FRAME_PHASE.
-        (STARTING_FRAME_PHASE): New.
-        (instantiate_virtual_regs): Check saneness of
-        STARTING_FRAME_PHASE.
+       * function.c (assign_stack_local_1): Adjust x_frame_offset with
+       STARTING_FRAME_PHASE.
+       (STARTING_FRAME_PHASE): New.
+       (instantiate_virtual_regs): Check saneness of
+       STARTING_FRAME_PHASE.
 
-        * config/rs6000/rs6000.h (STARTING_FRAME_PHASE): New.
+       * config/rs6000/rs6000.h (STARTING_FRAME_PHASE): New.
 
 2002-01-19  Alexandre Oliva  <aoliva@redhat.com>
 
@@ -327,11 +334,11 @@ Thu Jan 17 15:28:26 2002  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
 
 2002-01-17  Aldy Hernandez  <aldyh@redhat.com>
 
-        * config.gcc (cpu_type): Include altivec.h in powerpc
-        extra_headers.
-        Same for darwin.
+       * config.gcc (cpu_type): Include altivec.h in powerpc
+       extra_headers.
+       Same for darwin.
 
-        * config/rs6000/altivec.h: New.
+       * config/rs6000/altivec.h: New.
 
 2002-01-17  David Edelsohn  <edelsohn@gnu.org>
 
@@ -409,7 +416,7 @@ Thu Jan 17 15:28:26 2002  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
 2002-01-16  Jakub Jelinek  <jakub@redhat.com>
 
        PR target/5309:
-        * config/sparc/sparc.c (ultrasparc_adjust_cost): Handle TYPE_IDIV the
+       * config/sparc/sparc.c (ultrasparc_adjust_cost): Handle TYPE_IDIV the
        same way as TYPE_IMUL.
        (ultrasparc_sched_reorder): Likewise.
        * config/sparc/sparc.md (type): Add comment to update
@@ -505,27 +512,27 @@ Wed Jan 16 17:54:22 CET 2002  Jan Hubicka  <jh@suse.cz>
 
 2002-01-15  Aldy Hernandez  <aldyh@redhat.com>
 
-        * config/rs6000/rs6000.md (altivec_stvx): Add parallels to stvx.
-        (altivec_lvsl): Change constraint to b.
-        (altivec_lvsr): Same.
-        (altivec_lvebx): Same.
-        (altivec_lvehx): Same.
-        (altivec_lvewx): Same.
-        (altivec_lvxl): Same.
-        (altivec_lvx): Same.
-        (altivec_stvx): Add parallel.
-        (altivec_stvxl): Same.
-        (altivec_stvehx): Same.
-        (altivec_stvebx): Same.
-        (altivec_stvebx): Same.
+       * config/rs6000/rs6000.md (altivec_stvx): Add parallels to stvx.
+       (altivec_lvsl): Change constraint to b.
+       (altivec_lvsr): Same.
+       (altivec_lvebx): Same.
+       (altivec_lvehx): Same.
+       (altivec_lvewx): Same.
+       (altivec_lvxl): Same.
+       (altivec_lvx): Same.
+       (altivec_stvx): Add parallel.
+       (altivec_stvxl): Same.
+       (altivec_stvehx): Same.
+       (altivec_stvebx): Same.
+       (altivec_stvebx): Same.
 
 2002-01-15  Aldy Hernandez  <aldyh@redhat.com>
 
-        * config.gcc: Change altivec.h to altivec-defs.h.
+       * config.gcc: Change altivec.h to altivec-defs.h.
 
-        * config/rs6000/altivec.h: Delete.
+       * config/rs6000/altivec.h: Delete.
 
-        * config/rs6000/altivec-defs.h: Add.
+       * config/rs6000/altivec-defs.h: Add.
 
 2002-01-15  John David Anglin  <dave@hiauly1.hia.nrc.ca>
 
@@ -903,24 +910,24 @@ Fri Jan 11 09:25:05 2002  Nicola Pero  <n.pero@mi.flashnet.it>
 
 2002-01-10  Aldy Hernandez  <aldyh@redhat.com>
 
-        * config/rs6000/rs6000.c (altivec_init_builtins): Add support for
-        lvebx, lvehx, lvewx, lvxl, lvx, stvx, stvebx, stvehx, stvewx,
-        stvxl.
-        (altivec_expand_builtin): Same.
-        (altivec_expand_stv_builtin): New.
-
-        * config/rs6000/rs6000.h (rs6000_builtins): Same.
-
-        * config/rs6000/rs6000.md ("altivec_lvebx"): New.
-        ("altivec_lvehx"): New.
-        ("altivec_lvewx"): New.
-        ("altivec_lvxl"): New.
-        ("altivec_lvx"): New.
-        ("altivec_stvx"): New.
-        ("altivec_stvebx"): New.
-        ("altivec_stvehx"): New.
-        ("altivec_stvewx"): New.
-        ("altivec_stvxl"): New.
+       * config/rs6000/rs6000.c (altivec_init_builtins): Add support for
+       lvebx, lvehx, lvewx, lvxl, lvx, stvx, stvebx, stvehx, stvewx,
+       stvxl.
+       (altivec_expand_builtin): Same.
+       (altivec_expand_stv_builtin): New.
+
+       * config/rs6000/rs6000.h (rs6000_builtins): Same.
+
+       * config/rs6000/rs6000.md ("altivec_lvebx"): New.
+       ("altivec_lvehx"): New.
+       ("altivec_lvewx"): New.
+       ("altivec_lvxl"): New.
+       ("altivec_lvx"): New.
+       ("altivec_stvx"): New.
+       ("altivec_stvebx"): New.
+       ("altivec_stvehx"): New.
+       ("altivec_stvewx"): New.
+       ("altivec_stvxl"): New.
 
 2002-01-10  Richard Henderson  <rth@redhat.com>
 

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index ce93a03593a39be26453a666ffc960617b53452a..dec382d854e3c5275c5514ca98dd97642d3a8183 100644 (file)
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -1,6 +1,6 @@
 /* Fold a constant sub-tree into a single node for C-compiler
    Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001 Free Software Foundation, Inc.
+   1999, 2000, 2001, 2002 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -6753,6 +6753,31 @@ fold (expr)
                default:
                  break;
                }
+
+            else if (TREE_UNSIGNED (TREE_TYPE (arg1))
+                     && tree_int_cst_equal (TYPE_MAX_VALUE (TREE_TYPE (arg1)),
+                                            arg1))
+              switch (TREE_CODE (t))
+                {
+                case GT_EXPR:
+                  return omit_one_operand (type,
+                                           convert (type, integer_zero_node),
+                                           arg0);
+                case GE_EXPR:
+                  TREE_SET_CODE (t, EQ_EXPR);
+                  break;
+
+                case LE_EXPR:
+                  return omit_one_operand (type,
+                                           convert (type, integer_one_node),
+                                           arg0);
+                case LT_EXPR:
+                  TREE_SET_CODE (t, NE_EXPR);
+                  break;
+
+                default:
+                  break;
+                }
          }
       }