The following patch fixes
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78671
The patch was successfully bootstrapped and tested on x86-64.
Committed as rev. 243462.
Index: ChangeLog
===================================================================
--- ChangeLog (revision 243461)
+++ ChangeLog (working copy)
@@ -1,3 +1,9 @@
+2016-12-08 Vladimir Makarov <vmaka...@redhat.com>
+
+ PR rtl-optimization/78671
+ * lra-assign.c (lra-assigns.c): Check prohibited regs for an
+ allocno class.
+
2016-12-08 Uros Bizjak <ubiz...@gmail.com>
* gcc.target/i386/i386.h (HARD_REGNO_NREGS): Use GENERAL_REGNO_P.
Index: testsuite/ChangeLog
===================================================================
--- testsuite/ChangeLog (revision 243461)
+++ testsuite/ChangeLog (working copy)
@@ -1,3 +1,8 @@
+2016-12-08 Vladimir Makarov <vmaka...@redhat.com>
+
+ PR rtl-optimization/78671
+ * gcc.target/i386/pr78671.c: New.
+
2015-12-08 Wilco Dijkstra <wdijk...@arm.com>
PR target/78733
Index: lra-assigns.c
===================================================================
--- lra-assigns.c (revision 243305)
+++ lra-assigns.c (working copy)
@@ -628,9 +628,13 @@ find_hard_regno_for_1 (int regno, int *c
hard_regno = ira_class_hard_regs[rclass][i];
if (! overlaps_hard_reg_set_p (conflict_set,
PSEUDO_REGNO_MODE (regno), hard_regno)
- /* We can not use prohibited_class_mode_regs because it is
- not defined for all classes. */
&& HARD_REGNO_MODE_OK (hard_regno, PSEUDO_REGNO_MODE (regno))
+ /* We can not use prohibited_class_mode_regs for all classes
+ because it is not defined for all classes. */
+ && (ira_allocno_class_translate[rclass] != rclass
+ || ! TEST_HARD_REG_BIT (ira_prohibited_class_mode_regs
+ [rclass][PSEUDO_REGNO_MODE (regno)],
+ hard_regno))
&& ! TEST_HARD_REG_BIT (impossible_start_hard_regs, hard_regno)
&& (nregs_diff == 0
|| (WORDS_BIG_ENDIAN
Index: testsuite/gcc.target/i386/pr78671.c
===================================================================
--- testsuite/gcc.target/i386/pr78671.c (revision 0)
+++ testsuite/gcc.target/i386/pr78671.c (working copy)
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-march=skylake-avx512 -Og" } */
+
+typedef unsigned __int128 u128;
+typedef unsigned __int128 v64u128 __attribute__ ((vector_size (64)));
+
+v64u128
+foo (u128 u128_3, v64u128 v64u128_3, v64u128 v64u128_2, v64u128 v64u128_1,
+ v64u128 v64u128_0)
+{
+ v64u128_0 <<= 1;
+ v64u128_2 >>= 0 != v64u128_2;
+ v64u128_3[v64u128_3[0]] &= 1;
+ v64u128_3 = v64u128_3 & 1;
+ v64u128_2 = v64u128_2 >> 1 | v64u128_2 << v64u128_1[0];
+ v64u128_0[0] >>= 127;
+ return u128_3 + v64u128_0 + v64u128_2 + v64u128_3;
+}
