Partial fix for PR opt/10776

	Partial fix for PR opt/10776
	* Makefile.in (reload.o): Include param.h
	* params.def (PARAM_MAX_RELOAD_SEARCH_INSNS): New parameter.
	* reload.c: Include params.h.
	(find_equiv_reg): Work limiting check.
	* invoke.texi: Document.

From-SVN: r75679

5 files changed, 29 insertions, 2 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6d23396..5dee099 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2004-01-11  Jan Hubicka  <jh@suse.cz>
+
+	Partial fix for PR opt/10776
+	* Makefile.in (reload.o): Include param.h
+	* params.def (PARAM_MAX_RELOAD_SEARCH_INSNS): New parameter.
+	* reload.c: Include params.h.
+	(find_equiv_reg): Work limiting check.
+	* invoke.texi: Document.
+
 2004-01-11  Richard Sandiford  <rsandifo@redhat.com>
 
 	* config/mips/mips.c (mips_symbolic_constant_p): Don't allow
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 101408e..fde9b84 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1755,7 +1755,7 @@ ra-rewrite.o : ra-rewrite.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H)
    output.h except.h ra.h reload.h insn-config.h
 reload.o : reload.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) flags.h output.h \
    $(EXPR_H) $(OPTABS_H) reload.h $(RECOG_H) hard-reg-set.h insn-config.h \
-   $(REGS_H) function.h real.h toplev.h $(TM_P_H)
+   $(REGS_H) function.h real.h toplev.h $(TM_P_H) $(PARAMS_H)
 reload1.o : reload1.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) real.h flags.h \
    $(EXPR_H) $(OPTABS_H) reload.h $(REGS_H) hard-reg-set.h insn-config.h \
    $(BASIC_BLOCK_H) $(RECOG_H) output.h function.h toplev.h $(TM_P_H) \
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index b57ccd9..2431cc7 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -4853,6 +4853,14 @@ parameter very large effectively disables garbage collection.  Setting
 this parameter and @option{ggc-min-expand} to zero causes a full
 collection to occur at every opportunity.
 
+@table @gcctabopt
+@item max-reload-search-insns
+The maximum number of instruction reload should look backward for equivalent
+register.  Increasing values mean more aggressive optimization, making the
+compile time increase with probably slightly better performance.  The default
+value is 100.
+
+
 @item reorder-blocks-duplicate
 @itemx reorder-blocks-duplicate-feedback
 
diff --git a/gcc/params.def b/gcc/params.def
index d665ad5..a5b3099 100644
--- a/gcc/params.def
+++ b/gcc/params.def
@@ -260,6 +260,11 @@ DEFPARAM(GGC_MIN_HEAPSIZE,
 #undef GGC_MIN_EXPAND_DEFAULT
 #undef GGC_MIN_HEAPSIZE_DEFAULT
 
+DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
+	 "max-reload-search-insns",
+	 "The maximum number of instructions to search backward when looking for equivalent reload",
+	 100)
+
 /*
 Local variables:
 mode:c
diff --git a/gcc/reload.c b/gcc/reload.c
index 13f6900..361a502 100644
--- a/gcc/reload.c
+++ b/gcc/reload.c
@@ -104,6 +104,7 @@ a register with any other reload.  */
 #include "output.h"
 #include "function.h"
 #include "toplev.h"
+#include "params.h"
 
 #ifndef REGNO_MODE_OK_FOR_BASE_P
 #define REGNO_MODE_OK_FOR_BASE_P(REGNO, MODE) REGNO_OK_FOR_BASE_P (REGNO)
@@ -6383,6 +6384,7 @@ find_equiv_reg (rtx goal, rtx insn, enum reg_class class, int other,
   int need_stable_sp = 0;
   int nregs;
   int valuenregs;
+  int num = 0;
 
   if (goal == 0)
     regno = goalreg;
@@ -6423,6 +6425,7 @@ find_equiv_reg (rtx goal, rtx insn, enum reg_class class, int other,
   else
     return 0;
 
+  num = 0;
   /* Scan insns back from INSN, looking for one that copies
      a value into or out of GOAL.
      Stop and give up if we reach a label.  */
@@ -6430,7 +6433,9 @@ find_equiv_reg (rtx goal, rtx insn, enum reg_class class, int other,
   while (1)
     {
       p = PREV_INSN (p);
-      if (p == 0 || GET_CODE (p) == CODE_LABEL)
+      num++;
+      if (p == 0 || GET_CODE (p) == CODE_LABEL
+	  || num > PARAM_VALUE (PARAM_MAX_RELOAD_SEARCH_INSNS))
 	return 0;
 
       if (GET_CODE (p) == INSN