re PR tree-optimization/53265 (Warn when undefined behavior implies smaller iteration count)

	PR tree-optimization/53265
	* common.opt (Waggressive-loop-optimizations): New option.
	* tree-ssa-loop-niter.c: Include tree-pass.h.
	(do_warn_aggressive_loop_optimizations): New function.
	(record_estimate): Call it.  Don't add !is_exit bounds to loop->bounds
	if number_of_latch_executions returned constant.
	(estimate_numbers_of_iterations_loop): Call number_of_latch_executions
	early.  If number_of_latch_executions returned constant, set
	nb_iterations_upper_bound back to it.
	* cfgloop.h (struct loop): Add warned_aggressive_loop_optimizations
	field.
	* Makefile.in (tree-ssa-loop-niter.o): Depend on $(TREE_PASS_H).
	* doc/invoke.texi (-Wno-aggressive-loop-optimizations): Document.

	* gcc.dg/pr53265.c: New test.
	* gcc.dg/torture/pr49518.c: Add -Wno-aggressive-loop-optimizations
	to dg-options.
	* g++.dg/opt/longbranch2.C (EBCOTLut): Double sizes of a2 and a3
	arrays.
	* gcc.dg/tree-ssa/cunroll-10.c (main): Rename to foo.  Add argument
	n, use it as high bound instead of 4.

	* unwind-dw2.c (execute_cfa_program): Avoid
	-Waggressive-array-optimizations warnings for DW_CFA_GNU_window_save
	on targets with DWARF_FRAME_REGISTERS < 32.

	* testsuite/libmudflap.c/fail37-frag.c: Add optimization barrier.

From-SVN: r196650

1 files changed, 156 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/pr53265.c b/gcc/testsuite/gcc.dg/pr53265.c
new file mode 100644
index 0000000..c60a736
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr53265.c
@@ -0,0 +1,156 @@
+/* PR tree-optimization/53265 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wall" } */
+
+void bar (void *);
+int baz (int);
+
+void
+fn1 (void)
+{
+  unsigned int a[128];
+  int i;
+
+  for (i = 0; i < 128; ++i)	/* { dg-message "note: containing loop" } */
+    a[i] = i * 0x02000001;	/* { dg-warning "invokes undefined behavior" } */
+  bar (a);
+}
+
+void
+fn2 (void)
+{
+  unsigned long long a[128];
+  int i;
+
+  for (i = 0; i < 128; i++)			/* { dg-message "note: containing loop" } */
+    a[i] = (i + 1LL) * 0x0123456789ABCDEFLL;	/* { dg-warning "invokes undefined behavior" } */
+  bar (a);
+}
+
+void
+fn3 (void)
+{
+  unsigned char a[16], b[16], c[16];
+  int i;
+
+  bar (b);
+  for (i = 0; i < (int) (sizeof (a) / sizeof (a[0])); i++)	/* { dg-message "note: containing loop" } */
+    {
+      c[i + 8] = b[i];	/* { dg-warning "invokes undefined behavior" } */
+      a[i + 8] = b[i + 8];
+    }
+  bar (a);
+  bar (c);
+}
+
+void
+fn4 (void)
+{
+  unsigned int *a[32], *o, i;
+
+  bar (a);
+  for (i = 0; i <= sizeof (a) / sizeof (a[0]); i++)	/* { dg-message "note: containing loop" "" { xfail *-*-* } } */
+    {
+      o = a[i];	/* { dg-warning "invokes undefined behavior" "" { xfail *-*-* } } */
+      bar (o);
+    }
+}
+
+void
+fn5 (void)
+{
+  unsigned short a[23940];
+  unsigned int b[1140];
+  int j;
+
+  bar (b);
+  for (j = 0; j < 1140; j++)	/* { dg-message "note: containing loop" } */
+    a[23940 + j - 950] = b[j];	/* { dg-warning "invokes undefined behavior" } */
+  bar (a);
+}
+
+void
+fn6 (void)
+{
+  double a[4][3], b[12];
+  int i;
+  bar (b);
+  for (i = 0; i < 12; i++)	/* { dg-message "note: containing loop" } */
+    a[0][i] = b[i] / 10000.0;	/* { dg-warning "invokes undefined behavior" } */
+  bar (a);
+}
+
+void
+fn7 (void)
+{
+  int a[16], b, c;
+  bar (a);
+  for (b = a[c = 0]; c < 16; b = a[++c])	/* { dg-warning "invokes undefined behavior" "" { xfail *-*-* } } */
+    baz (b);
+}
+
+/* { dg-message "note: containing loop" "" { xfail *-*-* } 88 } */
+
+const void *va, *vb, *vc, *vd, *ve;
+const void *vf[4];
+void
+fn8 (void)
+{
+  unsigned long i;
+  vf[0] = va; vf[1] = vb; vf[2] = vc; vf[3] = vd;
+  for (i = 0; i < (sizeof (vf) / sizeof (vf[0])); i++)
+    if (!vf[i])
+      vf[i] = ve;
+}
+
+int wa, wb[53][5], wc[53][5];
+
+void
+fn9 (void)
+{
+  int i, j, k;
+  for (i = 0; i < 53; i++)
+    for (j = 16 / (((wa & 1) != 0) ? 8 : 4); j > 0; j--)
+      {
+	int d = 1;
+	if (wb[i][j] == 0 || wc[i][1] != 0)
+	  continue;
+	for (k = 0; k < j; k++)
+	  if (wc[i + k][1])
+	    {
+	      d = 0;
+	      break;
+	    }
+	if (!d)
+	  continue;
+	wc[i][j] = baz (0);
+      }
+}
+
+int xa[18];
+
+void
+fn10 (void)
+{
+  int i;
+  for (i = 16; i < 32; i++)	/* { dg-message "note: containing loop" } */
+    xa[i] = 26;			/* { dg-warning "invokes undefined behavior" } */
+}
+
+__attribute__((noinline)) static void
+fn11 (int x)
+{
+  int i = 1;
+  if (x > 1)
+    do
+      baz (i);
+    while (++i != x);		/* { dg-bogus "invokes undefined behavior" } */
+}
+
+void
+fn12 (void)
+{
+  fn11 (1);
+  fn11 (1);
+  fn11 (1);
+}