Overhaul sequence point warnings (again)

From-SVN: r37706

gcc/ChangeLog

@@ -3,6 +3,20 @@
 	* combine.c (cant_combine_insn_p): New function.
 	(try_combine): Use it.
 
+	* Makefile.in (c-common.o): Depend on $(OBSTACK_H).
+	* c-common.c (c-obstack.c): Include "obstack.h".
+	(struct reverse_tree): Delete.
+	(reverse_list, reverse_max_depth): Delete.
+	(build_reverse_tree, common_ancestor, modify_ok): Delete functions.
+	(struct tlist, struct tlist_cache): New.
+	(tlist_obstack, tlist_firstobj, warned_ids, save_expr_cache): New.
+	(add_tlist, merge_tlist, verify_tree, warning_candidate_p,
+	warn_for_collisions, warn_for_collisions_1, new_tlist): New
+	static functions.
+	(verify_sequence_points): Rewritten.
+	* fold-const.c (fold): Don't lose possibly important sequence
+	points when removing one arm of TRUTH_ORIF_EXPRs or TRUTH_ANDIF_EXPRs.
+
 2000-11-24  Richard Sandiford  <rsandifo@redhat.com>
 
 	* gcc/cse.c (cse_insn): Removed conversion of REG_EQUIV to REG_EQUAL

gcc/Makefile.in

@@ -1214,7 +1214,7 @@ s-under: $(GCC_PASSES)
 
 # A file used by all variants of C.
 
-c-common.o : c-common.c $(CONFIG_H) system.h $(TREE_H) \
+c-common.o : c-common.c $(CONFIG_H) system.h $(TREE_H) $(OBSTACK_H) \
 	$(C_COMMON_H) flags.h toplev.h output.h c-pragma.h $(RTL_H) $(GGC_H) \
 	$(EXPR_H) diagnostic.h
 

gcc/fold-const.c

@@ -5962,7 +5962,9 @@ fold (expr)
       /* If either arg is constant true, drop it.  */
       if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
 	return non_lvalue (convert (type, arg1));
-      if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
+      if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)
+	  /* Preserve sequence points.  */
+	  && (code != TRUTH_ANDIF_EXPR || ! TREE_SIDE_EFFECTS (arg0)))
 	return non_lvalue (convert (type, arg0));
       /* If second arg is constant zero, result is zero, but first arg
 	 must be evaluated.  */
@@ -6048,7 +6050,9 @@ fold (expr)
       /* If either arg is constant zero, drop it.  */
       if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
 	return non_lvalue (convert (type, arg1));
-      if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1))
+      if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1)
+	  /* Preserve sequence points.  */
+	  && (code != TRUTH_ORIF_EXPR || ! TREE_SIDE_EFFECTS (arg0)))
 	return non_lvalue (convert (type, arg0));
       /* If second arg is constant true, result is true, but we must
 	 evaluate first arg.  */

gcc/testsuite/ChangeLog

+2000-11-24  Bernd Schmidt  <bernds@redhat.co.uk>
+
+	* gcc.dg/sequence-point-1.c: Add some new tests.
+
 2000-11-24  Nathan Sidwell  <nathan@codesourcery.com>
 
 	* g++.old-deja/g++.other/vaarg4.C: New test.

gcc/testsuite/gcc.dg/sequence-pt-1.c

@@ -19,7 +19,7 @@ typedef __SIZE_TYPE__ size_t;
 
 void
 foo (int a, int b, int n, int p, int *ptr, struct s *sptr,
-     int *ap, int *bp, int **cp, char *ans)
+     int *ap, int *bp, int **cp, char *ans, int (*fnp[8])(int))
 {
   int len;
     
@@ -44,6 +44,9 @@ foo (int a, int b, int n, int p, int *ptr, struct s *sptr,
   a = (bp[a++] = b) + 1; /* { dg-warning "undefined" "sequence point warning" } */
   a = b++ * b++; /* { dg-warning "undefined" "sequence point warning" } */
   a = fnb (b++, b++); /* { dg-warning "undefined" "sequence point warning" } */
+  a = (*fnp[b++]) (b++); /* { dg-warning "undefined" "sequence point warning" } */
+  a = (*fnp[b]) (b++); /* { dg-warning "undefined" "sequence point warning" } */
+  a = (*fnp[b++]) (b); /* { dg-warning "undefined" "sequence point warning" } */
   *ap = fnc (ap++); /* { dg-warning "undefined" "sequence point warning" } */
   (a += b) + (a += n); /* { dg-warning "undefined" "sequence point warning" } */
   a =  (b, b++) + (b++, b); /* { dg-warning "undefined" "sequence point warning" } */
@@ -51,10 +54,25 @@ foo (int a, int b, int n, int p, int *ptr, struct s *sptr,
   ap[a+=1] += a; /* { dg-warning "undefined" "sequence point warning" } */
   ap[a++] += a++; /* { dg-warning "undefined" "sequence point warning" } */
   ap[a+=1] += a++; /* { dg-warning "undefined" "sequence point warning" } */
+  a = a++, b = a; /* { dg-warning "undefined" "sequence point warning" } */
+  b = a, a = a++; /* { dg-warning "undefined" "sequence point warning" } */
+  a = (b++ ? n : a) + b; /* { dg-warning "undefined" "sequence point warning" } */
+  b ? a = a++ : a; /* { dg-warning "undefined" "sequence point warning" } */
+  b ? a : a = a++; /* { dg-warning "undefined" "sequence point warning" } */
+  b && (a = a++); /* { dg-warning "undefined" "sequence point warning" } */
+  (a = a++) && b; /* { dg-warning "undefined" "sequence point warning" } */
+  b, (a = a++); /* { dg-warning "undefined" "sequence point warning" } */
+  (a = a++), b; /* { dg-warning "undefined" "sequence point warning" } */
+  a ^= b ^= a ^= b; /* { dg-warning "undefined" "sequence point warning" } */
 
+  a = a; /* { dg-bogus "undefined" "bogus sequence point warning" } */
   a = (a++ && 4); /* { dg-bogus "undefined" "bogus sequence point warning" } */
+  a = ! (a++ && 4); /* { dg-bogus "undefined" "bogus sequence point warning" } */
+  a = - (a++ && 4); /* { dg-bogus "undefined" "bogus sequence point warning" } */
+  a = (double) (a++ && 4); /* { dg-bogus "undefined" "bogus sequence point warning" } */
   len = sprintf (ans, "%d", len++); /* { dg-bogus "undefined" "bogus sequence point warning" } */
-  a = fn (a++); /* { dg-bogus "undefined" "sequence point warning" } */
+  a = fn (a++); /* { dg-bogus "undefined" "bogus sequence point warning" } */
+  b++, (b + b); /* { dg-bogus "undefined" "bogus sequence point warning" } */
   (a = b++), (a = b++); /* { dg-bogus "undefined" "bogus sequence point warning" } */
   a = (b++, b++); /* { dg-bogus "undefined" "bogus sequence point warning" } */
   a = b++ && b++; /* { dg-bogus "undefined" "bogus sequence point warning" } */
@@ -63,4 +81,30 @@ foo (int a, int b, int n, int p, int *ptr, struct s *sptr,
   a = (b++ ? a : b++); /* { dg-bogus "undefined" "bogus sequence point warning" } */
   ap[a++] += bp[b]; /* { dg-bogus "undefined" "bogus sequence point warning" } */
   ap[a += 1] += 1; /* { dg-bogus "undefined" "bogus sequence point warning" } */
+  *ptr < 128 ? *ptr++ : *(ptr += 2); /* { dg-bogus "undefined" "bogus sequence point warning" } */
+
+  /* The following will be represented internally with a tree consisting of
+     many duplicated SAVE_EXPRs.  This caused the previous version of the
+     sequence point warning code to fail by running out of virtual memory.  */
+  a = ((b & 1 ? 21 : 0)
+       | (b & 2 ? 22 : 0)
+       | (b & 3 ? 23 : 0)
+       | (b & 4 ? 24 : 0)
+       | (b & 5 ? 25 : 0)
+       | (b & 6 ? 26 : 0)
+       | (b & 7 ? 27 : 0)
+       | (b & 8 ? 28 : 0)
+       | (b & 9 ? 29 : 0)
+       | (b & 10 ? 30 : 0)
+       | (b & 11 ? 31 : 0)
+       | (b & 12 ? 32 : 0)
+       | (b & 13 ? 1 : 0)
+       | (b & 14 ? 2 : 0)
+       | (b & 15 ? 3 : 0)
+       | (b & 16 ? 4 : 0)
+       | (b & 17 ? 5 : 0)
+       | (b & 18 ? 6 : 0)
+       | (b & 19 ? 7 : 0)
+       | (b & 20 ? 8 : 0)
+       | (b & 21 ? 9 : 0));
 }