re PR rtl-optimization/79032 (unaligned memory access generated with LRA and optimiza...

	PR rtl-optimization/79032
	* lra-constraints.c (simplify_operand_subreg): In the MEM case, test
	the alignment of the adjusted memory reference against that of MODE,
	instead of the alignment of the original memory reference.

From-SVN: r244311

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3c8f977e317d95da3f1a15bea3f1747e7c8c0b82..00eabd0c1cd92ffb30c82ead1f5d9766856adb45 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2017-01-11  Eric Botcazou  <ebotcazou@adacore.com>
+
+       PR rtl-optimization/79032
+       * lra-constraints.c (simplify_operand_subreg): In the MEM case, test
+       the alignment of the adjusted memory reference against that of MODE,
+       instead of the alignment of the original memory reference.
+
 2017-01-11  Martin Jambor  <mjambor@suse.cz>
 
        * hsa.c (hsa_callable_function_p): Revert addition of DECL_ARTIFICIAL

diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index 5ada67a36ba94030e96508f72e64563ca9a23e99..7b0d2f4b85fca66fdec1b9c2265b1d409a5d3c48 100644 (file)
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -1505,15 +1505,15 @@ simplify_operand_subreg (int nop, machine_mode reg_mode)
                                  MEM_ADDR_SPACE (subst))))
        {
          /* If we change the address for a paradoxical subreg of memory, the
-            address might violate the necessary alignment or the access might
-            be slow.  So take this into consideration.  We need not worry
+            new address might violate the necessary alignment or the access
+            might be slow; take this into consideration.  We need not worry
             about accesses beyond allocated memory for paradoxical memory
             subregs as we don't substitute such equiv memory (see processing
             equivalences in function lra_constraints) and because for spilled
             pseudos we allocate stack memory enough for the biggest
             corresponding paradoxical subreg.  */
-         if (!(MEM_ALIGN (reg) < GET_MODE_ALIGNMENT (mode)
-               && SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (reg)))
+         if (!(MEM_ALIGN (subst) < GET_MODE_ALIGNMENT (mode)
+               && SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (subst)))
              || (MEM_ALIGN (reg) < GET_MODE_ALIGNMENT (innermode)
                  && SLOW_UNALIGNED_ACCESS (innermode, MEM_ALIGN (reg))))
            return true;

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f189a4484deed5a31ea51415e1b97e50e7c4ae22..c892d161ea0d742981220ba0d4e5822b44d287d5 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2017-01-11  Eric Botcazou  <ebotcazou@adacore.com>
+
+       * gcc.c-torture/execute/20170111-1.c: New test.
+
 2017-01-11  Richard Biener  <rguenther@suse.de>
 
        * gcc.dg/tree-ssa/pr61743-1.c: Adjust.

diff --git a/gcc/testsuite/gcc.c-torture/execute/20170111-1.c b/gcc/testsuite/gcc.c-torture/execute/20170111-1.c
new file mode 100644 (file)
index 0000000..0ff4bab
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20170111-1.c
@@ -0,0 +1,33 @@
+/* PR rtl-optimization/79032 */
+/* Reported by Daniel Cederman <cederman@gaisler.com> */
+
+extern void abort (void);
+
+struct S {
+  short a;
+  long long b;
+  short c;
+  char d;
+  unsigned short e;
+  long *f;
+};
+
+static long foo (struct S *s) __attribute__((noclone, noinline));
+
+static long foo (struct S *s)
+{
+  long a = 1;
+  a /= s->e;
+  s->f[a]--;
+  return a;
+}
+
+int main (void)
+{
+  long val = 1;
+  struct S s = { 0, 0, 0, 0, 2, &val };
+  val = foo (&s);
+  if (val != 0)
+    abort ();
+  return 0;
+}