re PR rtl-optimization/7871 (ICE on legal code, global register variables problems)

	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.

From-SVN: r78601

gcc/ChangeLog

+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.

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));
 		}
 	    }