[PATCH v2]: i386: Fix up ix86_md_asm_adjust for TImode [PR98086]

[Uros Bizjak via Gcc-patches]

ix86_md_asm_adjust assumes that dest_mode can be only [QHSD]Imode
and nothing else.  The patch rewrites zero-extension part to use
convert_to_mode to handle TImode and hypothetically even wider modes.

2020-12-03  Uroš Bizjak  <ubiz...@gmail.com>
        Jakub Jelinek  <ja...@redhat.com>

gcc/
    PR target/98086
    * config/i386/i386.c (ix86_md_asm_adjustmd): Rewrite
    zero-extension part to use convert_to_mode.

gcc/testsuite/
    PR target/98086
    * gcc.target/i386/pr98086.c: New test.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Pushed to master, will be backported to gcc-10 and gcc-9.

Uros.

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index c5db8c9712e..63216782430 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -21508,40 +21508,18 @@ ix86_md_asm_adjust (vec<rtx> &outputs, vec<rtx> 
&/*inputs*/,
          continue;
        }
 
-      if (dest_mode == DImode && !TARGET_64BIT)
-       dest_mode = SImode;
-
-      if (dest_mode != QImode)
-       {
-         rtx destqi = gen_reg_rtx (QImode);
-         emit_insn (gen_rtx_SET (destqi, x));
-
-         if (TARGET_ZERO_EXTEND_WITH_AND
-             && optimize_function_for_speed_p (cfun))
-           {
-             x = force_reg (dest_mode, const0_rtx);
-
-             emit_insn (gen_movstrictqi (gen_lowpart (QImode, x), destqi));
-           }
-         else
-           {
-             x = gen_rtx_ZERO_EXTEND (dest_mode, destqi);
-             if (dest_mode == GET_MODE (dest)
-                 && !register_operand (dest, GET_MODE (dest)))
-               x = force_reg (dest_mode, x);
-           }
-       }
-
-      if (dest_mode != GET_MODE (dest))
+      if (dest_mode == QImode)
+       emit_insn (gen_rtx_SET (dest, x));
+      else
        {
-         rtx tmp = gen_reg_rtx (SImode);
+         rtx reg = gen_reg_rtx (QImode);
+         emit_insn (gen_rtx_SET (reg, x));
 
-         emit_insn (gen_rtx_SET (tmp, x));
-         emit_insn (gen_zero_extendsidi2 (dest, tmp));
+         reg = convert_to_mode (dest_mode, reg, 1);
+         emit_move_insn (dest, reg);
        }
-      else
-       emit_insn (gen_rtx_SET (dest, x));
     }
+
   rtx_insn *seq = get_insns ();
   end_sequence ();
 
diff --git a/gcc/testsuite/gcc.target/i386/pr98086.c 
b/gcc/testsuite/gcc.target/i386/pr98086.c
new file mode 100644
index 00000000000..254a3b9bef6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr98086.c
@@ -0,0 +1,17 @@
+/* PR target/98086 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+#ifdef __x86_64__
+typedef __int128 T;
+#else
+typedef long long T;
+#endif
+
+T x;
+
+void
+foo (void)
+{
+  __asm ("" : "=@ccc" (x));
+}