PR optimization/7871

	* flow.c (mark_set_1): Don't add LOG_LINKS for global registers
	from or to call insns.
	(propagate_one_insn): Interpret calls as setting global registers,
	not merely clobbering them.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@78601 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5993005..879bbfc 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,4 +1,17 @@
+2004-02-27  Ian Lance Taylor  <ian@wasabisystems.com>
+
+       PR optimization/7871
+       * flow.c (mark_set_1): Don't add LOG_LINKS for global registers
+       from or to call insns.  
+
+2004-02-27  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+       PR optimization/7871
+       * flow.c (propagate_one_insn): Interpret calls as setting global
+       registers, not merely clobbering them.
+
 2004-02-27  Dale Johannesen  <dalej@apple.com>
+
        * config/darwin.c (machopic_output_possible_stub_label):  Remove.
        config/darwin-protos.h:  Ditto.
        config/darwin.h:  Remove call to it.

diff --git a/gcc/flow.c b/gcc/flow.c
index acf375a..66dbf1c 100644 (file)
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -1772,8 +1772,9 @@ propagate_one_insn (struct propagate_block_info *pbi, rtx insn)
                                              current_function_return_rtx,
                                              (rtx *) 0)))
              {
+               enum rtx_code code = global_regs[i] ? SET : CLOBBER;
                /* We do not want REG_UNUSED notes for these registers.  */
-               mark_set_1 (pbi, CLOBBER, regno_reg_rtx[i], cond, insn,
+               mark_set_1 (pbi, code, regno_reg_rtx[i], cond, insn,
                            pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
              }
        }
@@ -2799,10 +2800,18 @@ mark_set_1 (struct propagate_block_info *pbi, enum rtx_code code, rtx reg, rtx c
                     in ASM_OPERANDs.  If these registers get replaced,
                     we might wind up changing the semantics of the insn,
                     even if reload can make what appear to be valid
-                    assignments later.  */
+                    assignments later.
+
+                    We don't build a LOG_LINK for global registers to
+                    or from a function call.  We don't want to let
+                    combine think that it knows what is going on with
+                    global registers.  */
                  if (y && (BLOCK_NUM (y) == blocknum)
                      && (regno_first >= FIRST_PSEUDO_REGISTER
-                         || asm_noperands (PATTERN (y)) < 0))
+                         || (asm_noperands (PATTERN (y)) < 0
+                             && ! ((GET_CODE (insn) == CALL_INSN
+                                    || GET_CODE (y) == CALL_INSN)
+                                   && global_regs[regno_first]))))
                    LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
                }
            }