re PR middle-end/55555 (miscompilation at -O2 (number_of_iterations))

2012-12-18  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/55555
	* tree-ssa-loop-niter.c (idx_infer_loop_bounds): Properly
	analyze evolution of the index for the loop it is used in.
	* tree-scalar-evolution.c (instantiate_scev_name): Take
	inner loop we will be creating a chrec for.  Generalize
	fix for PR40281 and prune invalid SCEVs.
	(instantiate_scev_poly): Likewise - pass down inner loop
	we will be creating a chrec for.
	(instantiate_scev_binary): Take and pass through inner loop.
	(instantiate_array_ref): Likewise.
	(instantiate_scev_convert): Likewise.
	(instantiate_scev_not): Likewise.
	(instantiate_scev_3): Likewise.
	(instantiate_scev_2): Likewise.
	(instantiate_scev_1): Likewise.
	(instantiate_scev_r): Likewise.
	(resolve_mixers): Adjust.
	(instantiate_scev): Likewise.

	* gcc.dg/torture/pr55555.c: New testcase.
	* gcc.dg/vect/vect-iv-11.c: Adjust.

From-SVN: r194578

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 104fc9e6d76dfcb854a363cd23e5b82c5115ca31..b032c96abe9822968b8747a888abcfe1f6a049b3 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,24 @@
+2012-12-18  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/55555
+       * tree-ssa-loop-niter.c (idx_infer_loop_bounds): Properly
+       analyze evolution of the index for the loop it is used in.
+       * tree-scalar-evolution.c (instantiate_scev_name): Take
+       inner loop we will be creating a chrec for.  Generalize
+       fix for PR40281 and prune invalid SCEVs.
+       (instantiate_scev_poly): Likewise - pass down inner loop
+       we will be creating a chrec for.
+       (instantiate_scev_binary): Take and pass through inner loop.
+       (instantiate_array_ref): Likewise.
+       (instantiate_scev_convert): Likewise.
+       (instantiate_scev_not): Likewise.
+       (instantiate_scev_3): Likewise.
+       (instantiate_scev_2): Likewise.
+       (instantiate_scev_1): Likewise.
+       (instantiate_scev_r): Likewise.
+       (resolve_mixers): Adjust.
+       (instantiate_scev): Likewise.
+
 2012-12-18  Jakub Jelinek  <jakub@redhat.com>
 
        PR debug/55717

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2360147fba7d4d290e57419c0d31c58e29c66659..551236c95c5d3283e3c9f7fda9a0f3a4020e12d4 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2012-12-18  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/55555
+       * gcc.dg/torture/pr55555.c: New testcase.
+       * gcc.dg/vect/vect-iv-11.c: Adjust.
+
 2012-12-18  Jakub Jelinek  <jakub@redhat.com>
 
        PR debug/55717

diff --git a/gcc/testsuite/gcc.dg/torture/pr55555.c b/gcc/testsuite/gcc.dg/torture/pr55555.c
new file mode 100644 (file)
index 0000000..9e42266
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr55555.c
@@ -0,0 +1,34 @@
+/* { dg-do run } */
+
+double s[4] = { 1.0, 2.0, 3.0, 4.0 }, pol_x[2] = { 5.0, 6.0 };
+
+__attribute__((noinline)) int
+foo (void)
+{
+  double coef_x[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
+  int lxp = 0;
+  if (lxp <= 1)
+    do
+      {
+       double t = pol_x[lxp];
+       long S;
+       long l = lxp * 4L - 1;
+       for (S = 1; S <= 4; S++)
+         coef_x[S + l] = coef_x[S + l] + s[S - 1] * t;
+      }
+    while (lxp++ != 1);
+  asm volatile ("" : : "r" (coef_x) : "memory");
+  for (lxp = 0; lxp < 8; lxp++)
+    if (coef_x[lxp] != ((lxp & 3) + 1) * (5.0 + (lxp >= 4)))
+      __builtin_abort ();
+  return 1;
+}
+
+int
+main ()
+{
+  asm volatile ("" : : : "memory");
+  if (!foo ())
+    __builtin_abort ();
+  return 0;
+}

diff --git a/gcc/testsuite/gcc.dg/vect/vect-iv-11.c b/gcc/testsuite/gcc.dg/vect/vect-iv-11.c
index ef1c5774409c12e8bee3caefa69480117cb07940..632b97c29501f053292b6826cfba0a175cc08bc5 100644 (file)
--- a/gcc/testsuite/gcc.dg/vect/vect-iv-11.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-iv-11.c
@@ -3,7 +3,8 @@
 #include <stdarg.h>
 #include "tree-vect.h"
 
-int main1 (int len)
+int __attribute__((noinline,noclone))
+main1 (int len)
 {  
   int s = 0;
   int i = len;

diff --git a/gcc/tree-scalar-evolution.c b/gcc/tree-scalar-evolution.c
index d19154265e392a21671a0f5bf5f525cfbd223b69..9fc2f79ab89f358b15f50269cac196b7e66eae5c 100644 (file)
--- a/gcc/tree-scalar-evolution.c
+++ b/gcc/tree-scalar-evolution.c
@@ -2147,8 +2147,8 @@ loop_closed_phi_def (tree var)
   return NULL_TREE;
 }
 
-static tree instantiate_scev_r (basic_block, struct loop *, tree, bool,
-                               htab_t, int);
+static tree instantiate_scev_r (basic_block, struct loop *, struct loop *,
+                               tree, bool, htab_t, int);
 
 /* Analyze all the parameters of the chrec, between INSTANTIATE_BELOW
    and EVOLUTION_LOOP, that were left under a symbolic form.
@@ -2166,7 +2166,8 @@ static tree instantiate_scev_r (basic_block, struct loop *, tree, bool,
 
 static tree
 instantiate_scev_name (basic_block instantiate_below,
-                      struct loop *evolution_loop, tree chrec,
+                      struct loop *evolution_loop, struct loop *inner_loop,
+                      tree chrec,
                       bool fold_conversions, htab_t cache, int size_expr)
 {
   tree res;
@@ -2225,7 +2226,8 @@ instantiate_scev_name (basic_block instantiate_below,
          loop_p loop = loop_containing_stmt (SSA_NAME_DEF_STMT (chrec));
          res = analyze_scalar_evolution (loop, chrec);
          res = compute_overall_effect_of_inner_loop (loop, res);
-         res = instantiate_scev_r (instantiate_below, evolution_loop, res,
+         res = instantiate_scev_r (instantiate_below, evolution_loop,
+                                   inner_loop, res,
                                    fold_conversions, cache, size_expr);
        }
       else if (!dominated_by_p (CDI_DOMINATORS, instantiate_below,
@@ -2234,8 +2236,16 @@ instantiate_scev_name (basic_block instantiate_below,
     }
 
   else if (res != chrec_dont_know)
-    res = instantiate_scev_r (instantiate_below, evolution_loop, res,
-                             fold_conversions, cache, size_expr);
+    {
+      if (inner_loop
+         && !flow_loop_nested_p (def_bb->loop_father, inner_loop))
+       /* ???  We could try to compute the overall effect of the loop here.  */
+       res = chrec_dont_know;
+      else
+       res = instantiate_scev_r (instantiate_below, evolution_loop,
+                                 inner_loop, res,
+                                 fold_conversions, cache, size_expr);
+    }
 
   /* Store the correct value to the cache.  */
   set_instantiated_value (cache, instantiate_below, chrec, res);
@@ -2258,17 +2268,20 @@ instantiate_scev_name (basic_block instantiate_below,
 
 static tree
 instantiate_scev_poly (basic_block instantiate_below,
-                      struct loop *evolution_loop, tree chrec,
+                      struct loop *evolution_loop, struct loop *,
+                      tree chrec,
                       bool fold_conversions, htab_t cache, int size_expr)
 {
   tree op1;
   tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
+                                get_chrec_loop (chrec),
                                 CHREC_LEFT (chrec), fold_conversions, cache,
                                 size_expr);
   if (op0 == chrec_dont_know)
     return chrec_dont_know;
 
   op1 = instantiate_scev_r (instantiate_below, evolution_loop,
+                           get_chrec_loop (chrec),
                            CHREC_RIGHT (chrec), fold_conversions, cache,
                            size_expr);
   if (op1 == chrec_dont_know)
@@ -2277,19 +2290,8 @@ instantiate_scev_poly (basic_block instantiate_below,
   if (CHREC_LEFT (chrec) != op0
       || CHREC_RIGHT (chrec) != op1)
     {
-      unsigned var = CHREC_VARIABLE (chrec);
-
-      /* When the instantiated stride or base has an evolution in an
-        innermost loop, return chrec_dont_know, as this is not a
-        valid SCEV representation.  In the reduced testcase for
-        PR40281 we would have {0, +, {1, +, 1}_2}_1 that has no
-        meaning.  */
-      if ((tree_is_chrec (op0) && CHREC_VARIABLE (op0) > var)
-         || (tree_is_chrec (op1) && CHREC_VARIABLE (op1) > var))
-       return chrec_dont_know;
-
       op1 = chrec_convert_rhs (chrec_type (op0), op1, NULL);
-      chrec = build_polynomial_chrec (var, op0, op1);
+      chrec = build_polynomial_chrec (CHREC_VARIABLE (chrec), op0, op1);
     }
 
   return chrec;
@@ -2311,18 +2313,19 @@ instantiate_scev_poly (basic_block instantiate_below,
 
 static tree
 instantiate_scev_binary (basic_block instantiate_below,
-                        struct loop *evolution_loop, tree chrec, enum tree_code code,
+                        struct loop *evolution_loop, struct loop *inner_loop,
+                        tree chrec, enum tree_code code,
                         tree type, tree c0, tree c1,
                         bool fold_conversions, htab_t cache, int size_expr)
 {
   tree op1;
-  tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
+  tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, inner_loop,
                                 c0, fold_conversions, cache,
                                 size_expr);
   if (op0 == chrec_dont_know)
     return chrec_dont_know;
 
-  op1 = instantiate_scev_r (instantiate_below, evolution_loop,
+  op1 = instantiate_scev_r (instantiate_below, evolution_loop, inner_loop,
                            c1, fold_conversions, cache,
                            size_expr);
   if (op1 == chrec_dont_know)
@@ -2370,12 +2373,14 @@ instantiate_scev_binary (basic_block instantiate_below,
 
 static tree
 instantiate_array_ref (basic_block instantiate_below,
-                      struct loop *evolution_loop, tree chrec,
+                      struct loop *evolution_loop, struct loop *inner_loop,
+                      tree chrec,
                       bool fold_conversions, htab_t cache, int size_expr)
 {
   tree res;
   tree index = TREE_OPERAND (chrec, 1);
-  tree op1 = instantiate_scev_r (instantiate_below, evolution_loop, index,
+  tree op1 = instantiate_scev_r (instantiate_below, evolution_loop,
+                                inner_loop, index,
                                 fold_conversions, cache, size_expr);
 
   if (op1 == chrec_dont_know)
@@ -2406,11 +2411,13 @@ instantiate_array_ref (basic_block instantiate_below,
 
 static tree
 instantiate_scev_convert (basic_block instantiate_below,
-                         struct loop *evolution_loop, tree chrec,
+                         struct loop *evolution_loop, struct loop *inner_loop,
+                         tree chrec,
                          tree type, tree op,
                          bool fold_conversions, htab_t cache, int size_expr)
 {
-  tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, op,
+  tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
+                                inner_loop, op,
                                 fold_conversions, cache, size_expr);
 
   if (op0 == chrec_dont_know)
@@ -2453,11 +2460,13 @@ instantiate_scev_convert (basic_block instantiate_below,
 
 static tree
 instantiate_scev_not (basic_block instantiate_below,
-                     struct loop *evolution_loop, tree chrec,
+                     struct loop *evolution_loop, struct loop *inner_loop,
+                     tree chrec,
                      enum tree_code code, tree type, tree op,
                      bool fold_conversions, htab_t cache, int size_expr)
 {
-  tree op0 = instantiate_scev_r (instantiate_below, evolution_loop, op,
+  tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
+                                inner_loop, op,
                                 fold_conversions, cache, size_expr);
 
   if (op0 == chrec_dont_know)
@@ -2501,24 +2510,25 @@ instantiate_scev_not (basic_block instantiate_below,
 
 static tree
 instantiate_scev_3 (basic_block instantiate_below,
-                   struct loop *evolution_loop, tree chrec,
+                   struct loop *evolution_loop, struct loop *inner_loop,
+                   tree chrec,
                    bool fold_conversions, htab_t cache, int size_expr)
 {
   tree op1, op2;
   tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
-                                TREE_OPERAND (chrec, 0),
+                                inner_loop, TREE_OPERAND (chrec, 0),
                                 fold_conversions, cache, size_expr);
   if (op0 == chrec_dont_know)
     return chrec_dont_know;
 
   op1 = instantiate_scev_r (instantiate_below, evolution_loop,
-                           TREE_OPERAND (chrec, 1),
+                           inner_loop, TREE_OPERAND (chrec, 1),
                            fold_conversions, cache, size_expr);
   if (op1 == chrec_dont_know)
     return chrec_dont_know;
 
   op2 = instantiate_scev_r (instantiate_below, evolution_loop,
-                           TREE_OPERAND (chrec, 2),
+                           inner_loop, TREE_OPERAND (chrec, 2),
                            fold_conversions, cache, size_expr);
   if (op2 == chrec_dont_know)
     return chrec_dont_know;
@@ -2548,18 +2558,19 @@ instantiate_scev_3 (basic_block instantiate_below,
 
 static tree
 instantiate_scev_2 (basic_block instantiate_below,
-                   struct loop *evolution_loop, tree chrec,
+                   struct loop *evolution_loop, struct loop *inner_loop,
+                   tree chrec,
                    bool fold_conversions, htab_t cache, int size_expr)
 {
   tree op1;
   tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
-                                TREE_OPERAND (chrec, 0),
+                                inner_loop, TREE_OPERAND (chrec, 0),
                                 fold_conversions, cache, size_expr);
   if (op0 == chrec_dont_know)
     return chrec_dont_know;
 
   op1 = instantiate_scev_r (instantiate_below, evolution_loop,
-                           TREE_OPERAND (chrec, 1),
+                           inner_loop, TREE_OPERAND (chrec, 1),
                            fold_conversions, cache, size_expr);
   if (op1 == chrec_dont_know)
     return chrec_dont_know;
@@ -2587,11 +2598,12 @@ instantiate_scev_2 (basic_block instantiate_below,
 
 static tree
 instantiate_scev_1 (basic_block instantiate_below,
-                   struct loop *evolution_loop, tree chrec,
+                   struct loop *evolution_loop, struct loop *inner_loop,
+                   tree chrec,
                    bool fold_conversions, htab_t cache, int size_expr)
 {
   tree op0 = instantiate_scev_r (instantiate_below, evolution_loop,
-                                TREE_OPERAND (chrec, 0),
+                                inner_loop, TREE_OPERAND (chrec, 0),
                                 fold_conversions, cache, size_expr);
 
   if (op0 == chrec_dont_know)
@@ -2619,7 +2631,8 @@ instantiate_scev_1 (basic_block instantiate_below,
 
 static tree
 instantiate_scev_r (basic_block instantiate_below,
-                   struct loop *evolution_loop, tree chrec,
+                   struct loop *evolution_loop, struct loop *inner_loop,
+                   tree chrec,
                    bool fold_conversions, htab_t cache, int size_expr)
 {
   /* Give up if the expression is larger than the MAX that we allow.  */
@@ -2634,31 +2647,36 @@ instantiate_scev_r (basic_block instantiate_below,
   switch (TREE_CODE (chrec))
     {
     case SSA_NAME:
-      return instantiate_scev_name (instantiate_below, evolution_loop, chrec,
+      return instantiate_scev_name (instantiate_below, evolution_loop,
+                                   inner_loop, chrec,
                                    fold_conversions, cache, size_expr);
 
     case POLYNOMIAL_CHREC:
-      return instantiate_scev_poly (instantiate_below, evolution_loop, chrec,
+      return instantiate_scev_poly (instantiate_below, evolution_loop,
+                                   inner_loop, chrec,
                                    fold_conversions, cache, size_expr);
 
     case POINTER_PLUS_EXPR:
     case PLUS_EXPR:
     case MINUS_EXPR:
     case MULT_EXPR:
-      return instantiate_scev_binary (instantiate_below, evolution_loop, chrec,
+      return instantiate_scev_binary (instantiate_below, evolution_loop,
+                                     inner_loop, chrec,
                                      TREE_CODE (chrec), chrec_type (chrec),
                                      TREE_OPERAND (chrec, 0),
                                      TREE_OPERAND (chrec, 1),
                                      fold_conversions, cache, size_expr);
 
     CASE_CONVERT:
-      return instantiate_scev_convert (instantiate_below, evolution_loop, chrec,
+      return instantiate_scev_convert (instantiate_below, evolution_loop,
+                                      inner_loop, chrec,
                                       TREE_TYPE (chrec), TREE_OPERAND (chrec, 0),
                                       fold_conversions, cache, size_expr);
 
     case NEGATE_EXPR:
     case BIT_NOT_EXPR:
-      return instantiate_scev_not (instantiate_below, evolution_loop, chrec,
+      return instantiate_scev_not (instantiate_below, evolution_loop,
+                                  inner_loop, chrec,
                                   TREE_CODE (chrec), TREE_TYPE (chrec),
                                   TREE_OPERAND (chrec, 0),
                                   fold_conversions, cache, size_expr);
@@ -2671,7 +2689,8 @@ instantiate_scev_r (basic_block instantiate_below,
       return chrec_known;
 
     case ARRAY_REF:
-      return instantiate_array_ref (instantiate_below, evolution_loop, chrec,
+      return instantiate_array_ref (instantiate_below, evolution_loop,
+                                   inner_loop, chrec,
                                    fold_conversions, cache, size_expr);
 
     default:
@@ -2684,15 +2703,18 @@ instantiate_scev_r (basic_block instantiate_below,
   switch (TREE_CODE_LENGTH (TREE_CODE (chrec)))
     {
     case 3:
-      return instantiate_scev_3 (instantiate_below, evolution_loop, chrec,
+      return instantiate_scev_3 (instantiate_below, evolution_loop,
+                                inner_loop, chrec,
                                 fold_conversions, cache, size_expr);
 
     case 2:
-      return instantiate_scev_2 (instantiate_below, evolution_loop, chrec,
+      return instantiate_scev_2 (instantiate_below, evolution_loop,
+                                inner_loop, chrec,
                                 fold_conversions, cache, size_expr);
 
     case 1:
-      return instantiate_scev_1 (instantiate_below, evolution_loop, chrec,
+      return instantiate_scev_1 (instantiate_below, evolution_loop,
+                                inner_loop, chrec,
                                 fold_conversions, cache, size_expr);
 
     case 0:
@@ -2729,8 +2751,8 @@ instantiate_scev (basic_block instantiate_below, struct loop *evolution_loop,
       fprintf (dump_file, ")\n");
     }
 
-  res = instantiate_scev_r (instantiate_below, evolution_loop, chrec, false,
-                           cache, 0);
+  res = instantiate_scev_r (instantiate_below, evolution_loop,
+                           NULL, chrec, false, cache, 0);
 
   if (dump_file && (dump_flags & TDF_SCEV))
     {
@@ -2753,8 +2775,8 @@ tree
 resolve_mixers (struct loop *loop, tree chrec)
 {
   htab_t cache = htab_create (10, hash_scev_info, eq_scev_info, del_scev_info);
-  tree ret = instantiate_scev_r (block_before_loop (loop), loop, chrec, true,
-                                cache, 0);
+  tree ret = instantiate_scev_r (block_before_loop (loop), loop, NULL,
+                                chrec, true, cache, 0);
   htab_delete (cache);
   return ret;
 }

diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c
index a9b70778952981615af382f21783d7621f6830cd..4a09999f434b3ea0bab52960130cc8f0f270d5cd 100644 (file)
--- a/gcc/tree-ssa-loop-niter.c
+++ b/gcc/tree-ssa-loop-niter.c
@@ -2671,7 +2671,12 @@ idx_infer_loop_bounds (tree base, tree *idx, void *dta)
       upper = false;
     }
 
-  ev = instantiate_parameters (loop, analyze_scalar_evolution (loop, *idx));
+  struct loop *dloop = loop_containing_stmt (data->stmt);
+  if (!dloop)
+    return true;
+
+  ev = analyze_scalar_evolution (dloop, *idx);
+  ev = instantiate_parameters (loop, ev);
   init = initial_condition (ev);
   step = evolution_part_in_loop_num (ev, loop->num);