ira.c: Fix ICE in ira-color [PR97092]

gcc/ChangeLog

2020-12-10  Andrea Corallo  <andrea.corallo@arm.com>

	PR rtl-optimization/97092
	* ira-color.c (update_costs_from_allocno): Do not carry over mode
	between subsequent iterations.

gcc/testsuite/ChangeLog

2020-12-10  Andrea Corallo  <andrea.corallo@arm.com>

	* gcc.target/aarch64/sve/pr97092.c: New test.

diff --git a/gcc/ira-color.c b/gcc/ira-color.c
index d3f8e23faff61cab63a3ccb56f0cd464793ba3c4..eb525390494f68a44191e4783c51c1bbebe1e213 100644 (file)
--- a/gcc/ira-color.c
+++ b/gcc/ira-color.c
@@ -1407,9 +1407,11 @@ update_costs_from_allocno (ira_allocno_t allocno, int hard_regno,
             register classes bigger modes might be invalid,
             e.g. DImode for AREG on x86.  For such cases the
             register move cost will be maximal.  */
-         mode = narrower_subreg_mode (mode, ALLOCNO_MODE (cp->second));
+         mode = narrower_subreg_mode (ALLOCNO_MODE (cp->first),
+                                      ALLOCNO_MODE (cp->second));
+
          ira_init_register_move_cost_if_necessary (mode);
-         
+
          cost = (cp->second == allocno
                  ? ira_register_move_cost[mode][rclass][aclass]
                  : ira_register_move_cost[mode][aclass][rclass]);

diff --git a/gcc/testsuite/gcc.target/aarch64/sve/pr97092.c b/gcc/testsuite/gcc.target/aarch64/sve/pr97092.c
new file mode 100644 (file)
index 0000000..69f7a3e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/pr97092.c
@@ -0,0 +1,24 @@
+/* { dg-do assemble { target aarch64_asm_sve_ok } } */
+/* { dg-options "-O1 -ftree-vectorize -march=armv8.2-a+sve" } */
+
+void g (void);
+long a;
+
+signed char
+bar (int c, int d)
+{
+  return c + d;
+}
+
+void
+foo (void)
+{
+  int f;
+  for (; (long)foo < 4;) {
+    f = 0;
+    for (; f < 10; f++);
+    g ();
+    a = -4;
+    for (; a; a = bar (a, 1));
+  }
+}