[PATCH] x86: avoid maybe_gen_...()

[Jan Beulich via Gcc-patches]

In the (however unlikely) event that no insn can be found for the
requested mode, using maybe_gen_...() without (really) checking its
result for being a null rtx would lead to silent bad code generation.

gcc/

        * config/i386/i386-expand.cc (ix86_expand_vector_init_duplicate):
        Use gen_vec_set_0.
        (ix86_expand_vector_extract): Use gen_vec_extract_lo /
        gen_vec_extract_hi.
        (expand_vec_perm_broadcast_1): Use gen_vec_interleave_high /
        gen_vec_interleave_low. Rename local variable.

--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -15456,8 +15456,7 @@ ix86_expand_vector_init_duplicate (bool
            {
              tmp1 = force_reg (GET_MODE_INNER (mode), val);
              tmp2 = gen_reg_rtx (mode);
-             emit_insn (maybe_gen_vec_set_0 (mode, tmp2,
-                                             CONST0_RTX (mode), tmp1));
+             emit_insn (gen_vec_set_0 (mode, tmp2, CONST0_RTX (mode), tmp1));
              tmp1 = gen_lowpart (mode, tmp2);
            }
          else
@@ -17419,9 +17418,9 @@ ix86_expand_vector_extract (bool mmx_ok,
                 ? gen_reg_rtx (V16HFmode)
                 : gen_reg_rtx (V16BFmode));
          if (elt < 16)
-           emit_insn (maybe_gen_vec_extract_lo (mode, tmp, vec));
+           emit_insn (gen_vec_extract_lo (mode, tmp, vec));
          else
-           emit_insn (maybe_gen_vec_extract_hi (mode, tmp, vec));
+           emit_insn (gen_vec_extract_hi (mode, tmp, vec));
          ix86_expand_vector_extract (false, target, tmp, elt & 15);
          return;
        }
@@ -17435,9 +17434,9 @@ ix86_expand_vector_extract (bool mmx_ok,
                 ? gen_reg_rtx (V8HFmode)
                 : gen_reg_rtx (V8BFmode));
          if (elt < 8)
-           emit_insn (maybe_gen_vec_extract_lo (mode, tmp, vec));
+           emit_insn (gen_vec_extract_lo (mode, tmp, vec));
          else
-           emit_insn (maybe_gen_vec_extract_hi (mode, tmp, vec));
+           emit_insn (gen_vec_extract_hi (mode, tmp, vec));
          ix86_expand_vector_extract (false, target, tmp, elt & 7);
          return;
        }
@@ -22501,18 +22500,18 @@ expand_vec_perm_broadcast_1 (struct expa
       if (d->testing_p)
        return true;
 
-      rtx (*maybe_gen) (machine_mode, int, rtx, rtx, rtx);
+      rtx (*gen_interleave) (machine_mode, int, rtx, rtx, rtx);
       if (elt >= nelt2)
        {
-         maybe_gen = maybe_gen_vec_interleave_high;
+         gen_interleave = gen_vec_interleave_high;
          elt -= nelt2;
        }
       else
-       maybe_gen = maybe_gen_vec_interleave_low;
+       gen_interleave = gen_vec_interleave_low;
       nelt2 /= 2;
 
       dest = gen_reg_rtx (vmode);
-      emit_insn (maybe_gen (vmode, 1, dest, op0, op0));
+      emit_insn (gen_interleave (vmode, 1, dest, op0, op0));
 
       vmode = V4SImode;
       op0 = gen_lowpart (vmode, dest);