[PATCH] x86: Convert const0_rtx to non-int mode

[H.J. Lu]

From

(set (subreg:SI (reg/v:SF 105 [ f ]) 0)
     (const_int 0 [0]))

generate

(set (reg/v:SF 126 [ f ])
     (const_double:SF 0.0 [0x0.0p+0]))

instead of

(set (reg/v:SF 126 [ f ])
     (const_int 0 [0]))

gcc/

        PR target/124407
        * config/i386/i386-features.cc (ix86_broadcast_inner): Convert
        const0_rtx to non-int mode.

gcc/testsuite/

        PR target/124407
        * gcc.target/i386/pr124407.c: New test.

Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
---
 gcc/config/i386/i386-features.cc         | 11 +++++++++++
 gcc/testsuite/gcc.target/i386/pr124407.c | 15 +++++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr124407.c

diff --git a/gcc/config/i386/i386-features.cc b/gcc/config/i386/i386-features.cc
index 2604dad07b5..1338c564977 100644
--- a/gcc/config/i386/i386-features.cc
+++ b/gcc/config/i386/i386-features.cc
@@ -3780,6 +3780,17 @@ ix86_broadcast_inner (rtx op, machine_mode mode,
       op = src;
       if (mode != GET_MODE (reg))
        op = gen_int_mode (INTVAL (src), mode);
+      else if (!SCALAR_INT_MODE_P (mode))
+       {
+         /* Handle
+
+            (set (subreg:SI (reg/v:SF 105 [ f ]) 0)
+                 (const_int 0 [0]))
+         */
+         gcc_assert (op == const0_rtx);
+         op = CONST0_RTX (mode);
+       }
+
       *insn_p = nullptr;
     }
   else
diff --git a/gcc/testsuite/gcc.target/i386/pr124407.c 
b/gcc/testsuite/gcc.target/i386/pr124407.c
new file mode 100644
index 00000000000..7e87ab3ba57
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr124407.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -msse2" } */
+
+typedef __attribute__((__vector_size__(8))) float V;
+V v;
+
+void
+foo()
+{
+  int i;
+  float f;
+  __builtin_memcpy(&f, &i, 1);
+  v -= f;
+  v /= f;
+}
-- 
2.53.0