re PR rtl-optimization/5878 (gcc 3.1 breaks on C code generated by the Mercury compiler)

	PR 5878
	* config/arc/arc.h, config/cris/cris.h, config/i386/i386.h,
	config/m68k/m68k.h, config/s390/s390.h, config/sparc/sparc.h
	(PIC_OFFSET_TABLE_REGNUM): Conditionalize on flag_pic.

	* config/arm/arm.h config/i386/i386.h, config/m68k/m68k.h,
	config/sparc/sparc.h (CONDITIONAL_REGISTER_USAGE): Set
	PIC_OFFSET_TABLE_REGNUM based on INVALID_REGNUM not flag_pic.

	* config/arc/arc.h (CONDITIONAL_REGISTER_USAGE): New.
	* config/arm/arm.c (arm_pic_register): Init to INVALID_REGNUM.
	(arm_override_options): Set arm_pic_register if TARGET_APCS_STACK
	also.  Don't set it if not flag_pic.
	* config/i386/i386.c (ix86_save_reg): Trust PIC_OFFSET_TABLE_REGNUM
	to be INVALID_REGNUM when not used.

	* gcc.dg/20020312-2.c: New.

From-SVN: r50713

gcc/ChangeLog

+2002-03-12  Richard Henderson  <rth@redhat.com>
+
+	* config/arc/arc.h, config/cris/cris.h, config/i386/i386.h,
+	config/m68k/m68k.h, config/s390/s390.h, config/sparc/sparc.h
+	(PIC_OFFSET_TABLE_REGNUM): Conditionalize on flag_pic.
+
+	* config/arm/arm.h config/i386/i386.h, config/m68k/m68k.h,
+	config/sparc/sparc.h (CONDITIONAL_REGISTER_USAGE): Set
+	PIC_OFFSET_TABLE_REGNUM based on INVALID_REGNUM not flag_pic.
+
+	* config/arc/arc.h (CONDITIONAL_REGISTER_USAGE): New.
+	* config/arm/arm.c (arm_pic_register): Init to INVALID_REGNUM.
+	(arm_override_options): Set arm_pic_register if TARGET_APCS_STACK
+	also.  Don't set it if not flag_pic.
+	* config/i386/i386.c (ix86_save_reg): Trust PIC_OFFSET_TABLE_REGNUM
+	to be INVALID_REGNUM when not used.
+
 2002-03-13  Aldy Hernandez  <aldyh@redhat.com>
 
-        * expmed.c (store_bit_field): Reset alias set for memory.
-        (extract_bit_field): Same.
+	* expmed.c (store_bit_field): Reset alias set for memory.
+	(extract_bit_field): Same.
 
 2002-03-12  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
@@ -372,12 +389,12 @@ Sat Mar  9 07:20:01 2002  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
 
 2002-03-08  Aldy Hernandez  <aldyh@redhat.com>
 
-        * config/rs6000/rs6000.c (rs6000_va_arg): Fix alignment for
-        vectors.
+	* config/rs6000/rs6000.c (rs6000_va_arg): Fix alignment for
+	vectors.
 
 2002-03-08  Aldy Hernandez  <aldyh@redhat.com>
 
-        * config/rs6000/sysv4.h (BIGGEST_ALIGNMENT): Change for altivec.
+	* config/rs6000/sysv4.h (BIGGEST_ALIGNMENT): Change for altivec.
 
 Fri Mar  8 21:27:49 CET 2002  Jan Hubicka  <jh@suse.cz>
 
@@ -521,11 +538,11 @@ Thu Mar  7 16:33:54 CET 2002  Jan Hubicka  <jh@suse.cz>
 
 2002-03-07  Aldy Hernandez  <aldyh@redhat.com>
 
-        * doc/invoke.texi: Add documentation for -mabi=no-altivec.
+	* doc/invoke.texi: Add documentation for -mabi=no-altivec.
 
-        * config/rs6000/rs6000.c (rs6000_parse_abi_options): Add
-        -mabi=no-altivec
-        (alt_reg_names): Remove % for vrsave.
+	* config/rs6000/rs6000.c (rs6000_parse_abi_options): Add
+	-mabi=no-altivec
+	(alt_reg_names): Remove % for vrsave.
 
 2002-03-06  Richard Henderson  <rth@redhat.com>
 
@@ -537,7 +554,7 @@ Thu Mar  7 16:33:54 CET 2002  Jan Hubicka  <jh@suse.cz>
 
 2002-03-06  Ulrich Weigand  <uweigand@de.ibm.com>
 
-        * reload1.c (reload): Unshare all rtl after reload is done.
+	* reload1.c (reload): Unshare all rtl after reload is done.
 
 	* simplify-rtx.c (simplify_plus_minus): Do not abort,
 	but simply fail if the expression is too complex to simplify.
@@ -662,7 +679,7 @@ Tue Mar  5 18:31:27 CET 2002  Jan Hubicka  <jh@suse.cz>
 
 2002-03-05  Richard Henderson  <rth@redhat.com>
 
-        * rs6000.h (TOTAL_ALTIVEC_REGS): Fix off-by-one error.
+	* rs6000.h (TOTAL_ALTIVEC_REGS): Fix off-by-one error.
 
 2002-03-04  Geoffrey Keating  <geoffk@redhat.com>
 
@@ -709,10 +726,10 @@ Mon Mar  4 15:33:54 CET 2002  Jan Hubicka  <jh@suse.cz>
 
 2002-03-03  Aldy Hernandez  <aldyh@redhat.com>
 
-        * config.gcc (powerpc-*-eabialtivec*): Use t-ppcendian.
-        (powerpc-*-eabisimaltivec*): Same.
+	* config.gcc (powerpc-*-eabialtivec*): Use t-ppcendian.
+	(powerpc-*-eabisimaltivec*): Same.
 
-        * config/rs6000/t-ppcendian: New.
+	* config/rs6000/t-ppcendian: New.
 
 2002-03-04  Herman A.J. ten Brugge <Haj.Ten.Brugge@net.HCC.nl>
 

gcc/config/arc/arc.h

@@ -355,6 +355,16 @@ if (GET_MODE_CLASS (MODE) == MODE_INT		\
   48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,		\
   27, 28, 29, 30 }
 
+/* Macro to conditionally modify fixed_regs/call_used_regs.  */
+#define CONDITIONAL_REGISTER_USAGE			\
+do {							\
+  if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM)	\
+    {							\
+      fixed_regs[PIC_OFFSET_TABLE_REGNUM] = 1;		\
+      call_used_regs[PIC_OFFSET_TABLE_REGNUM] = 1;	\
+    }							\
+} while (0)
+
 /* Return number of consecutive hard regs needed starting at reg REGNO
    to hold something of mode MODE.
    This is ordinarily the length in words of a value of mode MODE
@@ -1152,7 +1162,7 @@ do {							\
    pointer and frame pointer registers.  If this macro is not defined, it
    is up to the machine-dependent files to allocate such a register (if
    necessary).  */
-#define PIC_OFFSET_TABLE_REGNUM 26
+#define PIC_OFFSET_TABLE_REGNUM  (flag_pic ? 26 : INVALID_REGNUM)
 
 /* Define this macro if the register defined by PIC_OFFSET_TABLE_REGNUM is
    clobbered by calls.  Do not define this macro if PIC_OFFSET_TABLE_REGNUM

gcc/config/arm/arm.c

@@ -268,7 +268,7 @@ enum machine_mode output_memory_reference_mode;
 
 /* The register number to be used for the PIC offset register.  */
 const char * arm_pic_register_string = NULL;
-int arm_pic_register = 9;
+int arm_pic_register = INVALID_REGNUM;
 
 /* Set to 1 when a return insn is output, this means that the epilogue
    is not needed.  */
@@ -651,8 +651,8 @@ arm_override_options ()
   
   /* If stack checking is disabled, we can use r10 as the PIC register,
      which keeps r9 available.  */
-  if (flag_pic && !TARGET_APCS_STACK)
-    arm_pic_register = 10;
+  if (flag_pic)
+    arm_pic_register = TARGET_APCS_STACK ? 9 : 10;
   
   if (TARGET_APCS_FLOAT)
     warning ("passing floating point arguments in fp regs not yet supported");
@@ -713,18 +713,16 @@ arm_override_options ()
 
   if (arm_pic_register_string != NULL)
     {
-      int pic_register;
-
+      int pic_register = decode_reg_name (arm_pic_register_string);
+      
       if (!flag_pic)
 	warning ("-mpic-register= is useless without -fpic");
 
-      pic_register = decode_reg_name (arm_pic_register_string);
-      
       /* Prevent the user from choosing an obviously stupid PIC register.  */
-      if (pic_register < 0 || call_used_regs[pic_register]
-	  || pic_register == HARD_FRAME_POINTER_REGNUM
-	  || pic_register == STACK_POINTER_REGNUM
-	  || pic_register >= PC_REGNUM)
+      else if (pic_register < 0 || call_used_regs[pic_register]
+	       || pic_register == HARD_FRAME_POINTER_REGNUM
+	       || pic_register == STACK_POINTER_REGNUM
+	       || pic_register >= PC_REGNUM)
 	error ("unable to use '%s' for PIC register", arm_pic_register_string);
       else
 	arm_pic_register = pic_register;

gcc/config/arm/arm.h

@@ -838,7 +838,7 @@ extern const char * structure_size_string;
 	   regno <= LAST_ARM_FP_REGNUM; ++regno)		\
 	fixed_regs[regno] = call_used_regs[regno] = 1;		\
     }								\
-  if (flag_pic)							\
+  if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM)		\
     {								\
       fixed_regs[PIC_OFFSET_TABLE_REGNUM] = 1;			\
       call_used_regs[PIC_OFFSET_TABLE_REGNUM] = 1;		\

gcc/config/cris/cris.h

@@ -1468,7 +1468,7 @@ call_ ## FUNC (void)						\
 
 /* Node: PIC */
 
-#define PIC_OFFSET_TABLE_REGNUM 0
+#define PIC_OFFSET_TABLE_REGNUM (flag_pic ? 0 : INVALID_REGNUM)
 
 #define LEGITIMATE_PIC_OPERAND_P(X) cris_legitimate_pic_operand (X)
 

gcc/config/i386/i386.c

@@ -3880,9 +3880,7 @@ ix86_save_reg (regno, maybe_eh_return)
      int regno;
      int maybe_eh_return;
 {
-  if (flag_pic
-      && ! TARGET_64BIT
-      && regno == PIC_OFFSET_TABLE_REGNUM
+  if (regno == PIC_OFFSET_TABLE_REGNUM
       && (current_function_uses_pic_offset_table
 	  || current_function_uses_const_pool
 	  || current_function_calls_eh_return))

gcc/config/i386/i386.h

@@ -937,7 +937,7 @@ do {									\
         call_used_regs[i] = (call_used_regs[i]				\
 			     & (TARGET_64BIT ? 2 : 1)) != 0;		\
       }									\
-    if (flag_pic && PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM)		\
+    if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM)			\
       {									\
 	fixed_regs[PIC_OFFSET_TABLE_REGNUM] = 1;			\
 	call_used_regs[PIC_OFFSET_TABLE_REGNUM] = 1;			\
@@ -1113,11 +1113,11 @@ do {									\
 #define STATIC_CHAIN_REGNUM (TARGET_64BIT ? FIRST_REX_INT_REG + 10 - 8 : 2)
 
 /* Register to hold the addressing base for position independent
-   code access to data items.
-   We don't use PIC pointer for 64bit mode.  Define the regnum to
-   dummy value to prevent gcc from pessimizing code dealing with EBX.
- */
-#define PIC_OFFSET_TABLE_REGNUM (TARGET_64BIT ? INVALID_REGNUM : 3)
+   code access to data items.  We don't use PIC pointer for 64bit
+   mode.  Define the regnum to dummy value to prevent gcc from
+   pessimizing code dealing with EBX.  */
+#define PIC_OFFSET_TABLE_REGNUM \
+  (TARGET_64BIT || !flag_pic ? INVALID_REGNUM : 3)
 
 /* Register in which address to store a structure value
    arrives in the function.  On the 386, the prologue

gcc/config/m68k/m68k.h

@@ -387,7 +387,7 @@ extern int target_flags;
 #endif
 
 /* This defines the register which is used to hold the offset table for PIC.  */
-#define PIC_OFFSET_TABLE_REGNUM 13
+#define PIC_OFFSET_TABLE_REGNUM (flag_pic ? 13 : INVALID_REGNUM)
 
 #ifndef SUPPORT_SUN_FPA
 
@@ -469,43 +469,43 @@ extern int target_flags;
 
 #ifdef SUPPORT_SUN_FPA
 
-#define CONDITIONAL_REGISTER_USAGE \
-{ 						\
-  int i; 					\
-  HARD_REG_SET x; 				\
-  if (! TARGET_FPA)				\
-    { 						\
-      COPY_HARD_REG_SET (x, reg_class_contents[(int)FPA_REGS]); \
-      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++ ) \
-       if (TEST_HARD_REG_BIT (x, i)) 		\
-	fixed_regs[i] = call_used_regs[i] = 1; 	\
-    } 						\
-  if (! TARGET_68881)				\
-    { 						\
-      COPY_HARD_REG_SET (x, reg_class_contents[(int)FP_REGS]); \
-      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++ ) \
-       if (TEST_HARD_REG_BIT (x, i)) 		\
-	fixed_regs[i] = call_used_regs[i] = 1; 	\
-    } 						\
-  if (flag_pic)					\
-    fixed_regs[PIC_OFFSET_TABLE_REGNUM]		\
-      = call_used_regs[PIC_OFFSET_TABLE_REGNUM] = 1;\
+#define CONDITIONAL_REGISTER_USAGE				\
+{ 								\
+  int i; 							\
+  HARD_REG_SET x; 						\
+  if (! TARGET_FPA)						\
+    { 								\
+      COPY_HARD_REG_SET (x, reg_class_contents[(int)FPA_REGS]);	\
+      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++ )		\
+       if (TEST_HARD_REG_BIT (x, i)) 				\
+	fixed_regs[i] = call_used_regs[i] = 1; 			\
+    } 								\
+  if (! TARGET_68881)						\
+    { 								\
+      COPY_HARD_REG_SET (x, reg_class_contents[(int)FP_REGS]);	\
+      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++ )		\
+       if (TEST_HARD_REG_BIT (x, i)) 				\
+	fixed_regs[i] = call_used_regs[i] = 1; 			\
+    } 								\
+  if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM)		\
+    fixed_regs[PIC_OFFSET_TABLE_REGNUM]				\
+      = call_used_regs[PIC_OFFSET_TABLE_REGNUM] = 1;		\
 }
 #else
-#define CONDITIONAL_REGISTER_USAGE \
-{ 						\
-  int i; 					\
-  HARD_REG_SET x; 				\
-  if (! TARGET_68881)				\
-    { 						\
-      COPY_HARD_REG_SET (x, reg_class_contents[(int)FP_REGS]); \
-      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++ ) \
-       if (TEST_HARD_REG_BIT (x, i)) 		\
-	fixed_regs[i] = call_used_regs[i] = 1; 	\
-    } 						\
-  if (flag_pic)					\
-    fixed_regs[PIC_OFFSET_TABLE_REGNUM]		\
-      = call_used_regs[PIC_OFFSET_TABLE_REGNUM] = 1;\
+#define CONDITIONAL_REGISTER_USAGE				\
+{ 								\
+  int i; 							\
+  HARD_REG_SET x; 						\
+  if (! TARGET_68881)						\
+    { 								\
+      COPY_HARD_REG_SET (x, reg_class_contents[(int)FP_REGS]);	\
+      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++ )		\
+       if (TEST_HARD_REG_BIT (x, i)) 				\
+	fixed_regs[i] = call_used_regs[i] = 1; 			\
+    } 								\
+  if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM)		\
+    fixed_regs[PIC_OFFSET_TABLE_REGNUM]				\
+      = call_used_regs[PIC_OFFSET_TABLE_REGNUM] = 1;		\
 }
 
 #endif /* defined SUPPORT_SUN_FPA */

gcc/config/s390/s390.h

@@ -249,7 +249,7 @@ if (INTEGRAL_MODE_P (MODE) &&	        	    	\
    GPR 14: Return registers holds the return address
    GPR 15: Stack pointer */
 
-#define PIC_OFFSET_TABLE_REGNUM 12
+#define PIC_OFFSET_TABLE_REGNUM (flag_pic ? 12 : INVALID_REGNUM)
 #define BASE_REGISTER 13
 #define RETURN_REGNUM 14
 #define STACK_POINTER_REGNUM 15

gcc/config/sparc/sparc.h

@@ -984,7 +984,7 @@ if (TARGET_ARCH64				\
 #define CONDITIONAL_REGISTER_USAGE				\
 do								\
   {								\
-    if (flag_pic)						\
+    if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM)		\
       {								\
 	fixed_regs[PIC_OFFSET_TABLE_REGNUM] = 1;		\
 	call_used_regs[PIC_OFFSET_TABLE_REGNUM] = 1;		\
@@ -1159,7 +1159,7 @@ extern int sparc_mode_class[];
 /* Register which holds offset table for position-independent
    data references.  */
 
-#define PIC_OFFSET_TABLE_REGNUM 23
+#define PIC_OFFSET_TABLE_REGNUM (flag_pic ? 23 : INVALID_REGNUM)
 
 /* Pick a default value we can notice from override_options:
    !v9: Default is on.

gcc/testsuite/gcc.dg/20020312-2.c

+/* PR 5878. 
+
+   We ICEd in verify_local_live_at_start because we incorrectly forced
+   the PIC register live between BAR and BAZ.  We did this because the
+   definition of PIC_OFFSET_TABLE_REGNUM was incorrectly not INVALID_REGNUM
+   when !flag_pic for most targets.  */
+
+/* { dg-do run } */
+/* { dg-options "-O -fno-pic" } */
+
+#if #cpu(a29k)
+/* No pic register.  */
+#elif defined(__alpha__)
+/* PIC register is $29, but is used even without -fpic.  */
+#elif defined(__arc__)
+# define PIC_REG  "26"
+#elif defined(__arm__)
+# define PIC_REG  "9"
+#elif defined(AVR)
+/* No pic register.  */
+#elif defined(__clipper__)
+/* No pic register.  */
+#elif defined(__convex__)
+/* No pic register.  */
+#elif defined(__cris__)
+# define PIC_REG  "0"
+#elif defined(__D30V__)
+/* No pic register.  */
+#elif defined(__dsp1600__)
+/* No pic register.  */
+#elif defined(__elxsi__)
+/* No pic register.  */
+#elif defined(__fr30__)
+/* No pic register.  */
+#elif defined(__H8300__) || defined(__H8300H__) || defined(__H8300S__)
+/* No pic register.  */
+#elif #cpu(i370)
+/* No pic register.  */
+#elif defined(__i386__)
+# define PIC_REG  "ebx"
+#elif defined(__i860__)
+/* No pic register.  */
+#elif defined(__i960__)
+/* No pic register.  */
+#elif defined(__ia64__)
+/* PIC register is r1, but is used even without -fpic.  */
+#elif defined(__M32R__)
+/* No pic register.  */
+#elif defined(__m68k__)
+# define PIC_REG  "a5"
+#elif defined(__m88k__)
+# define PIC_REG  "25"
+#elif defined(__mc68hc1x__)
+/* No pic register.  */
+#elif defined(__mcore__)
+/* No pic register.  */
+#elif defined(__mips__)
+/* PIC register is $28, but is used even without -fpic.  */
+#elif defined(__mn10200__)
+/* No pic register.  */
+#elif defined(__mn10300__)
+/* No pic register.  */
+#elif #cpu(ns32k)
+/* No pic register.  */
+#elif defined(__parisc__)
+/* PIC register is %r27 or %r19, but is used even without -fpic.  */
+#elif defined(__pdp11__)
+/* No pic register.  */
+#elif defined(__pj__)
+/* No pic register.  */
+#elif defined(__powerpc__)
+# ifdef __darwin__
+#  define PIC_REG  "31"
+# else
+#  define PIC_REG  "30"
+# endif
+#elif defined(__ibm032__) /* aka romp */
+/* No pic register.  */
+#elif defined(__s390__)
+# define PIC_REG  "12"
+#elif defined(__sparc__)
+# define PIC_REG  "l7"
+#elif defined(__v850)
+/* No pic register.  */
+#elif defined(__vax__)
+/* No pic register.  */
+#elif defined(__we32000__)
+/* No pic register.  */
+#elif defined(__xstormy16__)
+/* No pic register.  */
+#elif defined(__XTENSA__)
+/* No pic register.  */
+#else
+# error "Modify the test for your target."
+#endif
+
+#ifdef PIC_REG
+register void *reg __asm__(PIC_REG);
+#else
+/* We really need a global register variable set to the PIC register
+   to expose the bug.  Oh well, let the test case not fail.  */
+static void *reg;
+#endif
+
+void * __attribute__((noinline))
+dummy (void *x)
+{
+  return x;
+}
+
+void
+f (void)
+{
+  goto *dummy (&&bar);
+  for (;;)
+    {
+    foo:
+      reg = (void *) 1;
+      if (!reg)
+        goto baz;
+      reg = &&foo;
+    }
+
+ bar:
+ baz:
+  reg = 0;
+}
+
+int
+main()
+{
+  void *old_reg = reg;
+  reg = (void *) 1;
+  f ();
+  if (reg)
+    abort ();
+  reg = old_reg;
+  return 0;
+}