[gcc r14-6844] rs6000: Correct definition of macro of fixed point efficient unaligned
HaoChen Gui
guihaoc@gcc.gnu.org
Wed Dec 27 02:37:48 GMT 2023
https://gcc.gnu.org/g:78bd9e25601a2b7162ad71f714861a05cf994488
commit r14-6844-g78bd9e25601a2b7162ad71f714861a05cf994488
Author: Haochen Gui <guihaoc@gcc.gnu.org>
Date: Wed Dec 27 10:30:06 2023 +0800
rs6000: Correct definition of macro of fixed point efficient unaligned
Marco TARGET_EFFICIENT_OVERLAPPING_UNALIGNED is used in rs6000-string.cc
to guard the platform which is efficient on fixed point unaligned
load/store. It's originally defined by TARGET_EFFICIENT_UNALIGNED_VSX
which is enabled from P8 and can be disabled by mno-vsx option. So the
definition is improper. This patch corrects it and call
slow_unaligned_access to judge if fixed point unaligned load/store is
efficient or not.
gcc/
* config/rs6000/rs6000.h (TARGET_EFFICIENT_OVERLAPPING_UNALIGNED):
Remove.
* config/rs6000/rs6000-string.cc (select_block_compare_mode):
Replace TARGET_EFFICIENT_OVERLAPPING_UNALIGNED with
targetm.slow_unaligned_access.
(expand_block_compare_gpr): Likewise.
(expand_block_compare): Likewise.
(expand_strncmp_gpr_sequence): Likewise.
gcc/testsuite/
* gcc.target/powerpc/block-cmp-1.c: New.
* gcc.target/powerpc/block-cmp-2.c: New.
Diff:
---
gcc/config/rs6000/rs6000-string.cc | 15 +++++++++------
gcc/config/rs6000/rs6000.h | 4 ----
gcc/testsuite/gcc.target/powerpc/block-cmp-1.c | 11 +++++++++++
gcc/testsuite/gcc.target/powerpc/block-cmp-2.c | 12 ++++++++++++
4 files changed, 32 insertions(+), 10 deletions(-)
diff --git a/gcc/config/rs6000/rs6000-string.cc b/gcc/config/rs6000/rs6000-string.cc
index 44a946cd453..fa80298470e 100644
--- a/gcc/config/rs6000/rs6000-string.cc
+++ b/gcc/config/rs6000/rs6000-string.cc
@@ -305,7 +305,7 @@ select_block_compare_mode (unsigned HOST_WIDE_INT offset,
else if (bytes == GET_MODE_SIZE (QImode))
return QImode;
else if (bytes < GET_MODE_SIZE (SImode)
- && TARGET_EFFICIENT_OVERLAPPING_UNALIGNED
+ && !targetm.slow_unaligned_access (SImode, align * BITS_PER_UNIT)
&& offset >= GET_MODE_SIZE (SImode) - bytes)
/* This matches the case were we have SImode and 3 bytes
and offset >= 1 and permits us to move back one and overlap
@@ -313,7 +313,7 @@ select_block_compare_mode (unsigned HOST_WIDE_INT offset,
unwanted bytes off of the input. */
return SImode;
else if (word_mode_ok && bytes < UNITS_PER_WORD
- && TARGET_EFFICIENT_OVERLAPPING_UNALIGNED
+ && !targetm.slow_unaligned_access (word_mode, align * BITS_PER_UNIT)
&& offset >= UNITS_PER_WORD-bytes)
/* Similarly, if we can use DImode it will get matched here and
can do an overlapping read that ends at the end of the block. */
@@ -1749,7 +1749,8 @@ expand_block_compare_gpr(unsigned HOST_WIDE_INT bytes, unsigned int base_align,
load_mode_size = GET_MODE_SIZE (load_mode);
if (bytes >= load_mode_size)
cmp_bytes = load_mode_size;
- else if (TARGET_EFFICIENT_OVERLAPPING_UNALIGNED)
+ else if (!targetm.slow_unaligned_access (load_mode,
+ align * BITS_PER_UNIT))
{
/* Move this load back so it doesn't go past the end.
P8/P9 can do this efficiently. */
@@ -1987,7 +1988,8 @@ expand_block_compare (rtx operands[])
if (!CONST_INT_P (align_rtx))
return false;
- unsigned int base_align = UINTVAL (align_rtx) / BITS_PER_UNIT;
+ unsigned int align_by_bits = UINTVAL (align_rtx);
+ unsigned int base_align = align_by_bits / BITS_PER_UNIT;
gcc_assert (GET_MODE (target) == SImode);
@@ -2026,7 +2028,7 @@ expand_block_compare (rtx operands[])
/* The code generated for p7 and older is not faster than glibc
memcmp if alignment is small and length is not short, so bail
out to avoid those conditions. */
- if (!TARGET_EFFICIENT_OVERLAPPING_UNALIGNED
+ if (targetm.slow_unaligned_access (word_mode, align_by_bits)
&& ((base_align == 1 && bytes > 16)
|| (base_align == 2 && bytes > 32)))
return false;
@@ -2168,7 +2170,8 @@ expand_strncmp_gpr_sequence (unsigned HOST_WIDE_INT bytes_to_compare,
load_mode_size = GET_MODE_SIZE (load_mode);
if (bytes_to_compare >= load_mode_size)
cmp_bytes = load_mode_size;
- else if (TARGET_EFFICIENT_OVERLAPPING_UNALIGNED)
+ else if (!targetm.slow_unaligned_access (load_mode,
+ align * BITS_PER_UNIT))
{
/* Move this load back so it doesn't go past the end.
P8/P9 can do this efficiently. */
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index 98e046f87eb..00a8f3d363f 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -485,10 +485,6 @@ extern int rs6000_vector_align[];
#define TARGET_NO_SF_SUBREG TARGET_DIRECT_MOVE_64BIT
#define TARGET_ALLOW_SF_SUBREG (!TARGET_DIRECT_MOVE_64BIT)
-/* This wants to be set for p8 and newer. On p7, overlapping unaligned
- loads are slow. */
-#define TARGET_EFFICIENT_OVERLAPPING_UNALIGNED TARGET_EFFICIENT_UNALIGNED_VSX
-
/* Byte/char syncs were added as phased in for ISA 2.06B, but are not present
in power7, so conditionalize them on p8 features. TImode syncs need quad
memory support. */
diff --git a/gcc/testsuite/gcc.target/powerpc/block-cmp-1.c b/gcc/testsuite/gcc.target/powerpc/block-cmp-1.c
new file mode 100644
index 00000000000..bcf0cb2ab4f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/block-cmp-1.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mdejagnu-cpu=power8 -mno-vsx" } */
+/* { dg-final { scan-assembler-not {\mb[l]? memcmp\M} } } */
+
+/* Test that it still can do expand for memcmpsi instead of calling library
+ on P8 with vsx disabled. */
+
+int foo (const char* s1, const char* s2)
+{
+ return __builtin_memcmp (s1, s2, 20);
+}
diff --git a/gcc/testsuite/gcc.target/powerpc/block-cmp-2.c b/gcc/testsuite/gcc.target/powerpc/block-cmp-2.c
new file mode 100644
index 00000000000..dfee15b2147
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/block-cmp-2.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target opt_mstrict_align } */
+/* { dg-options "-O2 -mstrict-align" } */
+/* { dg-final { scan-assembler-times {\mb[l]? memcmp\M} 1 } } */
+
+/* Test that it calls library for block memory compare when strict-align
+ is set. The flag causes rs6000_slow_unaligned_access returns true. */
+
+int foo (const char* s1, const char* s2)
+{
+ return __builtin_memcmp (s1, s2, 20);
+}
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