On 12/02/2015 04:09 PM, Nathan Sidwell wrote:
+/* Output a pattern for a move instruction. */
+
+const char *
+nvptx_output_mov_insn (rtx dst, rtx src)
+{
+ machine_mode dst_mode = GET_MODE (dst);
+ machine_mode dst_inner = (GET_CODE (dst) == SUBREG
+ ? GET_MODE (XEXP (dst, 0)) : dst_mode);
+ machine_mode src_inner = (GET_CODE (src) == SUBREG
+ ? GET_MODE (XEXP (src, 0)) : dst_mode);
+
+ if (REG_P (dst) && REGNO (dst) == NVPTX_RETURN_REGNUM && dst_mode == HImode)
+ /* Special handling for the return register. It's never really an
+ HI object, and only occurs as the destination of a move
+ insn. */
+ dst_inner = SImode;
+
+ if (src_inner == dst_inner)
+ return "%.\tmov%t0\t%0, %1;";
+
+ if (CONSTANT_P (src))
+ return (GET_MODE_CLASS (dst_inner) == MODE_INT
+ && GET_MODE_CLASS (src_inner) != MODE_FLOAT
+ ? "%.\tmov%t0\t%0, %1;" : "%.\tmov.b%T0\t%0, %1;");
Hi,
src_inner uses dst_mode rather than GET_MODE (src). I'm trying to
understand if that is intentional or not.
F.i., for this insn:
....
(insn 7 6 8 2
(set (reg:QI 67)
(const_int 1 [0x1])) 2 {*movqi_insn}
(nil))
...
when entering nvptx_output_mov_insn we have:
- GET_MODE (dst) == QI and GET_MODE (src) == VOID, but
- dst_inner == QI and src_inner == QI
So we handle this insn using this clause:
...
if (src_inner == dst_inner)
return "%.\tmov%t0\t%0, %1;";
...
rather than using the const handling clause:
...
if (CONSTANT_P (src))
return (GET_MODE_CLASS (dst_inner) == MODE_INT
&& GET_MODE_CLASS (src_inner) != MODE_FLOAT
? "%.\tmov%t0\t%0, %1;" : "%.\tmov.b%T0\t%0, %1;");
...
Using attached patch, we get dst_inner == QI and src_inner == VOID, and
the insn is handled by the const handling clause instead, and the same
string is returned as before.
I can imagine that src_inner uses dst_mode to avoid setting src_inner to
VOIDmode (in which case a comment explaining that would avoid the
impression of a copy-pasto). But AFAICT, it's not necessary.
Thanks,
- Tom
Fix src_inner in nvptx_output_mov_insn
---
gcc/config/nvptx/nvptx.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/gcc/config/nvptx/nvptx.c b/gcc/config/nvptx/nvptx.c
index 4c35c16..6951e27 100644
--- a/gcc/config/nvptx/nvptx.c
+++ b/gcc/config/nvptx/nvptx.c
@@ -2146,10 +2146,11 @@ const char *
nvptx_output_mov_insn (rtx dst, rtx src)
{
machine_mode dst_mode = GET_MODE (dst);
+ machine_mode src_mode = GET_MODE (src);
machine_mode dst_inner = (GET_CODE (dst) == SUBREG
? GET_MODE (XEXP (dst, 0)) : dst_mode);
machine_mode src_inner = (GET_CODE (src) == SUBREG
- ? GET_MODE (XEXP (src, 0)) : dst_mode);
+ ? GET_MODE (XEXP (src, 0)) : src_mode);
rtx sym = src;
if (GET_CODE (sym) == CONST)
