[gcc r14-1902] i386: Two minor tweaks to ix86_expand_move.

[gcc r14-1902] i386: Two minor tweaks to ix86_expand_move.

[Roger Sayle]

https://gcc.gnu.org/g:96c3539f2a38134cb76d8ab2e924e0dc70b2ccbd

commit r14-1902-g96c3539f2a38134cb76d8ab2e924e0dc70b2ccbd
Author: Roger Sayle <roger@nextmovesoftware.com>
Date:   Sat Jun 17 22:28:40 2023 +0100

    i386: Two minor tweaks to ix86_expand_move.
    
    This patch splits out two (independent) minor changes to i386-expand.cc's
    ix86_expand_move from a larger patch, given that it's better to review
    and commit these independent pieces separately from a more complex patch.
    
    The first change is to test for CONST_WIDE_INT_P before calling
    ix86_convert_const_wide_int_to_broadcast.  Whilst stepping through
    this function in gdb, I was surprised that the code was continually
    jumping into this function with operands that obviously weren't
    appropriate.
    
    The second change is to generalize the optimization for efficiently
    moving a TImode value to V1TImode (via V2DImode), to cover all 128-bit
    vector modes.
    
    Hence for the test case:
    
    typedef unsigned long uv2di __attribute__ ((__vector_size__ (16)));
    uv2di foo2(__int128 x) { return (uv2di)x; }
    
    we'd previously move via memory with:
    
    foo2:   movq    %rdi, -24(%rsp)
            movq    %rsi, -16(%rsp)
            movdqa  -24(%rsp), %xmm0
            ret
    
    with this patch we now generate with -O2 (the same as V1TImode):
    
    foo2:   movq    %rdi, %xmm0
            movq    %rsi, %xmm1
            punpcklqdq      %xmm1, %xmm0
            ret
    
    and with -O2 -msse4 the even better:
    
    foo2:   movq    %rdi, %xmm0
            pinsrq  $1, %rsi, %xmm0
            ret
    
    The new test case is unimaginatively called sse2-v1ti-mov-2.c given
    the original test case just for V1TI mode was called sse2-v1ti-mov-1.c.
    
    2023-06-17  Roger Sayle  <roger@nextmovesoftware.com>
    
    gcc/ChangeLog
            * config/i386/i386-expand.cc (ix86_expand_move): Check that OP1 is
            CONST_WIDE_INT_P before calling ix86_convert_wide_int_to_broadcast.
            Generalize special case for converting TImode to V1TImode to handle
            all 128-bit vector conversions.
    
    gcc/testsuite/ChangeLog
            * gcc.target/i386/sse2-v1ti-mov-2.c: New test case.

Diff:
---
 gcc/config/i386/i386-expand.cc                  | 10 ++++++----
 gcc/testsuite/gcc.target/i386/sse2-v1ti-mov-2.c | 16 ++++++++++++++++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index def060ab562..6a28b6767a7 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -521,7 +521,8 @@ ix86_expand_move (machine_mode mode, rtx operands[])
 		  return;
 		}
 	    }
-	  else if (GET_MODE_SIZE (mode) >= 16)
+	  else if (CONST_WIDE_INT_P (op1)
+		   && GET_MODE_SIZE (mode) >= 16)
 	    {
 	      rtx tmp = ix86_convert_const_wide_int_to_broadcast
 		(GET_MODE (op0), op1);
@@ -696,8 +697,9 @@ ix86_expand_vector_move (machine_mode mode, rtx operands[])
       return;
     }
 
-  /* Special case TImode to V1TImode conversions, via V2DI.  */
-  if (mode == V1TImode
+  /* Special case TImode to 128-bit vector conversions via V2DI.  */
+  if (VECTOR_MODE_P (mode)
+      && GET_MODE_SIZE (mode) == 16
       && SUBREG_P (op1)
       && GET_MODE (SUBREG_REG (op1)) == TImode
       && TARGET_64BIT && TARGET_SSE
@@ -709,7 +711,7 @@ ix86_expand_vector_move (machine_mode mode, rtx operands[])
       emit_move_insn (lo, gen_lowpart (DImode, SUBREG_REG (op1)));
       emit_move_insn (hi, gen_highpart (DImode, SUBREG_REG (op1)));
       emit_insn (gen_vec_concatv2di (tmp, lo, hi));
-      emit_move_insn (op0, gen_lowpart (V1TImode, tmp));
+      emit_move_insn (op0, gen_lowpart (mode, tmp));
       return;
     }
 
diff --git a/gcc/testsuite/gcc.target/i386/sse2-v1ti-mov-2.c b/gcc/testsuite/gcc.target/i386/sse2-v1ti-mov-2.c
new file mode 100644
index 00000000000..7e890857678
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/sse2-v1ti-mov-2.c
@@ -0,0 +1,16 @@
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2 -msse2" } */
+
+typedef unsigned __int128 uv1ti __attribute__ ((__vector_size__ (16)));
+typedef unsigned long uv2di __attribute__ ((__vector_size__ (16)));
+typedef unsigned int uv4si __attribute__ ((__vector_size__ (16)));
+typedef unsigned short uv8hi __attribute__ ((__vector_size__ (16)));
+typedef unsigned char uv16qi __attribute__ ((__vector_size__ (16)));
+
+uv1ti foo1(__int128 x) { return (uv1ti)x; }
+uv2di foo2(__int128 x) { return (uv2di)x; }
+uv4si foo4(__int128 x) { return (uv4si)x; }
+uv8hi foo8(__int128 x) { return (uv8hi)x; }
+uv16qi foo16(__int128 x) { return (uv16qi)x; }
+
+/* { dg-final { scan-assembler-not "%\[er\]sp" } } */