[committed] alpha: Fix computation mode in alpha_emit_set_long_cost [PR106966]

[Uros Bizjak via Gcc-patches]

    PR target/106966

gcc/ChangeLog:

    * config/alpha/alpha.cc (alpha_emit_set_long_const):
    Always use DImode when constructing long const.

gcc/testsuite/ChangeLog:

    * gcc.target/alpha/pr106966.c: New test.

Bootstrapped and regression tested by Matthias on alpha-linux-gnu.

Uros.

diff --git a/gcc/config/alpha/alpha.cc b/gcc/config/alpha/alpha.cc
index 360b50e20d4..beeab06a1aa 100644
--- a/gcc/config/alpha/alpha.cc
+++ b/gcc/config/alpha/alpha.cc
@@ -2070,6 +2070,8 @@ static rtx
 alpha_emit_set_long_const (rtx target, HOST_WIDE_INT c1)
 {
   HOST_WIDE_INT d1, d2, d3, d4;
+  machine_mode mode = GET_MODE (target);
+  rtx orig_target = target;
 
   /* Decompose the entire word */
 
@@ -2082,6 +2084,9 @@ alpha_emit_set_long_const (rtx target, HOST_WIDE_INT c1)
   d4 = ((c1 & 0xffffffff) ^ 0x80000000) - 0x80000000;
   gcc_assert (c1 == d4);
 
+  if (mode != DImode)
+    target = gen_lowpart (DImode, target);
+
   /* Construct the high word */
   if (d4)
     {
@@ -2101,7 +2106,7 @@ alpha_emit_set_long_const (rtx target, HOST_WIDE_INT c1)
   if (d1)
     emit_move_insn (target, gen_rtx_PLUS (DImode, target, GEN_INT (d1)));
 
-  return target;
+  return orig_target;
 }
 
 /* Given an integral CONST_INT or CONST_VECTOR, return the low 64 bits.  */
diff --git a/gcc/testsuite/gcc.target/alpha/pr106966.c 
b/gcc/testsuite/gcc.target/alpha/pr106966.c
new file mode 100644
index 00000000000..7145c2096c6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/alpha/pr106966.c
@@ -0,0 +1,13 @@
+/* PR target/106906 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -mbuild-constants" } */
+
+void
+do_console (unsigned short *vga)
+{
+  vga[0] = 'H';
+  vga[1] = 'e';
+  vga[2] = 'l';
+  vga[3] = 'l';
+  vga[4] = 'o';
+}