[PATCH v3 3/7] i386: Use GET_MODE with lowpart_subreg

[H.J. Lu]

With expand_promote_outgoing_argument, op3 in

  op3 = lowpart_subreg (QImode, op3, HImode);

may not be in HImode.  Call lowpart_subreg on op3 only if it isn't integer
constant and pass GET_MODE (op3) to lowpart_subreg instead of HImode.

        PR middle-end/14907
        * config/i386/i386-expand.cc (ix86_expand_builtin): Use GET_MODE
        with lowpart_subreg.

Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
---
 gcc/config/i386/i386-expand.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index ce887d96f6a..4c7aa316ae5 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -15532,7 +15532,8 @@ rdseed_step:
            op0 = copy_to_mode_reg (GET_MODE (op0), op0);
          emit_insn (gen (half, op0));
          op0 = half;
-         op3 = lowpart_subreg (QImode, op3, HImode);
+         if (!CONST_INT_P (op3))
+           op3 = lowpart_subreg (QImode, op3, GET_MODE (op3));
          break;
        case IX86_BUILTIN_GATHER3ALTDIV8SF:
        case IX86_BUILTIN_GATHER3ALTDIV8SI:
-- 
2.47.0