https://gcc.gnu.org/g:ae53e4b99eaad43424f2b0cc1bbabb3b454fb6d8
commit r15-3060-gae53e4b99eaad43424f2b0cc1bbabb3b454fb6d8
Author: Kewen Lin <li...@linux.ibm.com>
Date: Wed Aug 21 00:26:20 2024 -0500
rs6000: Fix vsx_le_perm_store_* splitters for !reload_completed
For vsx_le_perm_store_* we have two splitters, one is for
!reload_completed and the other is for reload_completed.
As Richard pointed out in [1], operand 1 here is a pure
input for DF and most passes, but it could be used as the
vector rotation (64 bit) destination of itself, so we
re-compute the source (back to the original value) for
the case reload_completed, while for !reload_completed we
generate one new pseudo, so both cases are fine if operand
1 is still live after this insn. But according to the
source code, for !reload_completed case, it can logically
reuse the operand 1 as the new pseudo generation is
conditional on can_create_pseudo_p, then it can cause
wrong result once operand 1 is live. So considering this
and there is no splitting for this when reload_in_progress,
this patch is to fix the code to assert can_create_pseudo_p
there, so that both !reload_completed and reload_completed
cases would ensure operand 1 is unchanged (pure input), it
is also prepared for the following up patch which would
strip the unnecessary INOUT constraint modifier "+".
This also fixes an oversight in the splitter for VSX_LE_128
(!reload_completed), it should use operand 1 rather than
operand 0.
[1] https://gcc.gnu.org/pipermail/gcc-patches/2024-August/660145.html
gcc/ChangeLog:
* config/rs6000/vsx.md
(*vsx_le_perm_store_{<VSX_D:mode>,<VSX_W:mode>,
v8hi,v16qi,<VSX_LE_128:mode>} !reload_completed splitters): Assert
can_create_pseudo_p and always generate one new pseudo for operand
1.
Diff:
---
gcc/config/rs6000/vsx.md | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/gcc/config/rs6000/vsx.md b/gcc/config/rs6000/vsx.md
index 27069d070e15..89eaef183d99 100644
--- a/gcc/config/rs6000/vsx.md
+++ b/gcc/config/rs6000/vsx.md
@@ -703,8 +703,8 @@
/* Otherwise, fall through to transform into a swapping store. */
}
- operands[2] = can_create_pseudo_p () ? gen_reg_rtx_and_attrs (operands[1])
- : operands[1];
+ gcc_assert (can_create_pseudo_p ());
+ operands[2] = gen_reg_rtx_and_attrs (operands[1]);
})
;; The post-reload split requires that we re-permute the source
@@ -775,8 +775,8 @@
/* Otherwise, fall through to transform into a swapping store. */
}
- operands[2] = can_create_pseudo_p () ? gen_reg_rtx_and_attrs (operands[1])
- : operands[1];
+ gcc_assert (can_create_pseudo_p ());
+ operands[2] = gen_reg_rtx_and_attrs (operands[1]);
})
;; The post-reload split requires that we re-permute the source
@@ -854,8 +854,8 @@
/* Otherwise, fall through to transform into a swapping store. */
}
- operands[2] = can_create_pseudo_p () ? gen_reg_rtx_and_attrs (operands[1])
- : operands[1];
+ gcc_assert (can_create_pseudo_p ());
+ operands[2] = gen_reg_rtx_and_attrs (operands[1]);
})
;; The post-reload split requires that we re-permute the source
@@ -947,8 +947,8 @@
/* Otherwise, fall through to transform into a swapping store. */
}
- operands[2] = can_create_pseudo_p () ? gen_reg_rtx_and_attrs (operands[1])
- : operands[1];
+ gcc_assert (can_create_pseudo_p ());
+ operands[2] = gen_reg_rtx_and_attrs (operands[1]);
})
;; The post-reload split requires that we re-permute the source
@@ -1076,9 +1076,8 @@
&& !altivec_indexed_or_indirect_operand (operands[0], <MODE>mode)"
[(const_int 0)]
{
- rtx tmp = (can_create_pseudo_p ()
- ? gen_reg_rtx_and_attrs (operands[0])
- : operands[0]);
+ gcc_assert (can_create_pseudo_p ());
+ rtx tmp = gen_reg_rtx_and_attrs (operands[1]);
rs6000_emit_le_vsx_permute (tmp, operands[1], <MODE>mode);
rs6000_emit_le_vsx_permute (operands[0], tmp, <MODE>mode);
DONE;
