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* [gcc r13-1906] PR target/106450: Tweak timode_remove_non_convertible_regs on x86_64.
@ 2022-07-31 20:47 Roger Sayle
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From: Roger Sayle @ 2022-07-31 20:47 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:493f4e6cf081ea2d016547629b29d130c1533ccb
commit r13-1906-g493f4e6cf081ea2d016547629b29d130c1533ccb
Author: Roger Sayle <roger@nextmovesoftware.com>
Date: Sun Jul 31 21:44:51 2022 +0100
PR target/106450: Tweak timode_remove_non_convertible_regs on x86_64.
This patch resolves PR target/106450, some more fall-out from more
aggressive TImode scalar-to-vector (STV) optimizations. I continue
to be caught out by how far TImode STV has diverged from DImode/SImode
STV, and therefore requires additional (unexpected) tweaking. Many
thanks to H.J. Lu for pointing out timode_remove_non_convertible_regs
needs to be extended to handle XOR (and other new operations).
Unhelpfully the comment above this function states that it's the TImode
version of "remove_non_convertible_regs", which doesn't exist anymore,
so I've resurrected an explanatory comment from the git history.
By refactoring the checks for hard regs and already "marked" regs
into timode_check_non_convertible_regs itself, all of its callers are
simplified. This patch then FOR_EACH_INSN_USE and FOR_EACH_INSN_DEF
to generically handle arbitrary (non-move) instructions (including
unary and binary operations), calling timode_check_non_convertible_regs
on each TImode register USE and DEF.
2022-07-31 Roger Sayle <roger@nextmovesoftware.com>
H.J. Lu <hjl.tools@gmail.com>
gcc/ChangeLog
PR target/106450
* config/i386/i386-features.cc (timode_check_non_convertible_regs):
Do nothing if REGNO is set in the REGS bitmap, or is a hard reg.
(timode_remove_non_convertible_regs): Update comment.
Call timode_check_non_convertible_reg on all TImode register
DEFs and USEs in each instruction.
gcc/testsuite/ChangeLog
PR target/106450
* gcc.target/i386/pr106450.c: New test case.
Diff:
---
gcc/config/i386/i386-features.cc | 46 ++++++++++++++++++--------------
gcc/testsuite/gcc.target/i386/pr106450.c | 14 ++++++++++
2 files changed, 40 insertions(+), 20 deletions(-)
diff --git a/gcc/config/i386/i386-features.cc b/gcc/config/i386/i386-features.cc
index aa5de714edb..e4cc4a30590 100644
--- a/gcc/config/i386/i386-features.cc
+++ b/gcc/config/i386/i386-features.cc
@@ -1808,6 +1808,11 @@ static void
timode_check_non_convertible_regs (bitmap candidates, bitmap regs,
unsigned int regno)
{
+ /* Do nothing if REGNO is already in REGS or is a hard reg. */
+ if (bitmap_bit_p (regs, regno)
+ || HARD_REGISTER_NUM_P (regno))
+ return;
+
for (df_ref def = DF_REG_DEF_CHAIN (regno);
def;
def = DF_REF_NEXT_REG (def))
@@ -1843,7 +1848,13 @@ timode_check_non_convertible_regs (bitmap candidates, bitmap regs,
}
}
-/* The TImode version of remove_non_convertible_regs. */
+/* For a given bitmap of insn UIDs scans all instructions and
+ remove insn from CANDIDATES in case it has both convertible
+ and not convertible definitions.
+
+ All insns in a bitmap are conversion candidates according to
+ scalar_to_vector_candidate_p. Currently it implies all insns
+ are single_set. */
static void
timode_remove_non_convertible_regs (bitmap candidates)
@@ -1857,25 +1868,20 @@ timode_remove_non_convertible_regs (bitmap candidates)
changed = false;
EXECUTE_IF_SET_IN_BITMAP (candidates, 0, id, bi)
{
- rtx def_set = single_set (DF_INSN_UID_GET (id)->insn);
- rtx dest = SET_DEST (def_set);
- rtx src = SET_SRC (def_set);
-
- if ((!REG_P (dest)
- || bitmap_bit_p (regs, REGNO (dest))
- || HARD_REGISTER_P (dest))
- && (!REG_P (src)
- || bitmap_bit_p (regs, REGNO (src))
- || HARD_REGISTER_P (src)))
- continue;
-
- if (REG_P (dest))
- timode_check_non_convertible_regs (candidates, regs,
- REGNO (dest));
-
- if (REG_P (src))
- timode_check_non_convertible_regs (candidates, regs,
- REGNO (src));
+ rtx_insn *insn = DF_INSN_UID_GET (id)->insn;
+ df_ref ref;
+
+ FOR_EACH_INSN_DEF (ref, insn)
+ if (!DF_REF_REG_MEM_P (ref)
+ && GET_MODE (DF_REF_REG (ref)) == TImode)
+ timode_check_non_convertible_regs (candidates, regs,
+ DF_REF_REGNO (ref));
+
+ FOR_EACH_INSN_USE (ref, insn)
+ if (!DF_REF_REG_MEM_P (ref)
+ && GET_MODE (DF_REF_REG (ref)) == TImode)
+ timode_check_non_convertible_regs (candidates, regs,
+ DF_REF_REGNO (ref));
}
EXECUTE_IF_SET_IN_BITMAP (regs, 0, id, bi)
diff --git a/gcc/testsuite/gcc.target/i386/pr106450.c b/gcc/testsuite/gcc.target/i386/pr106450.c
new file mode 100644
index 00000000000..d16231f6abd
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr106450.c
@@ -0,0 +1,14 @@
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2 -fsplit-paths" } */
+
+__int128 n;
+
+__attribute__ ((simd)) void
+foo (void)
+{
+ __int128 uninitialized;
+ unsigned __int128 *p = &n;
+
+ n >>= *p ? : 2;
+ n |= uninitialized;
+}
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2022-07-31 20:47 [gcc r13-1906] PR target/106450: Tweak timode_remove_non_convertible_regs on x86_64 Roger Sayle
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