We have to be able to choose one signedness for the epilogue
part of the reduction - for MIN/MAX this means if we have two
both have to be of the same signedness.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
Richard.
2019-11-05 Richard Biener <rguent...@suse.de>
PR tree-optimization/92324
* tree-vect-loop.c (check_reduction_path): For MIN/MAX require
all signed or unsigned operations.
* gcc.dg/vect/pr92324-3.c: New testcase.
Index: gcc/tree-vect-loop.c
===================================================================
--- gcc/tree-vect-loop.c (revision 277782)
+++ gcc/tree-vect-loop.c (working copy)
@@ -2744,6 +2744,7 @@ pop:
/* Check whether the reduction path detected is valid. */
bool fail = path.length () == 0;
bool neg = false;
+ int sign = -1;
*code = ERROR_MARK;
for (unsigned i = 1; i < path.length (); ++i)
{
@@ -2787,12 +2788,22 @@ pop:
TREE_TYPE (gimple_assign_rhs1 (use_stmt))))
;
else if (*code == ERROR_MARK)
- *code = use_code;
+ {
+ *code = use_code;
+ sign = TYPE_SIGN (TREE_TYPE (gimple_assign_lhs (use_stmt)));
+ }
else if (use_code != *code)
{
fail = true;
break;
}
+ else if ((use_code == MIN_EXPR
+ || use_code == MAX_EXPR)
+ && sign != TYPE_SIGN (TREE_TYPE (gimple_assign_lhs (use_stmt))))
+ {
+ fail = true;
+ break;
+ }
}
return ! fail && ! neg && *code != ERROR_MARK;
}
Index: gcc/testsuite/gcc.dg/vect/pr92324-3.c
===================================================================
--- gcc/testsuite/gcc.dg/vect/pr92324-3.c (nonexistent)
+++ gcc/testsuite/gcc.dg/vect/pr92324-3.c (working copy)
@@ -0,0 +1,27 @@
+#include "tree-vect.h"
+
+int a[1024];
+unsigned b[1024];
+
+int __attribute__((noipa))
+foo (int n)
+{
+ int res = 0;
+ for (int i = 0; i < n; ++i)
+ {
+ res = res > a[i] ? res : a[i];
+ res = res > b[i] ? res : b[i];
+ }
+ return res;
+}
+
+int main ()
+{
+ check_vect ();
+ b[3] = (unsigned)__INT_MAX__ + 1;
+ if (foo (4) != -__INT_MAX__ - 1)
+ __builtin_abort ();
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump-not "vectorized \[1-9\] loops" "vect" } } */
