Here is updated patch.
Also with corresponding target attribute, option default disabled.
gcc/ChangeLog:
* config/i386/i386-options.c (ix86_target_string): Handle
-mvect-compare-costs.
(ix86_valid_target_attribute_inner_p): Support target attribute
vect-compare-costs.
* config/i386/i386.c (ix86_autovectorize_vector_modes): Return
1 when TARGET_X86_VECT_COMPARE_COSTS.
* config/i386/i386.opt: Add option -mvect-compare-costs.
* doc/invoke.texi: Document -mvect-compare-costs.
---
gcc/config/i386/i386-options.c | 7 ++++++-
gcc/config/i386/i386.c | 5 ++++-
gcc/config/i386/i386.opt | 5 +++++
gcc/doc/invoke.texi | 7 ++++++-
4 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/gcc/config/i386/i386-options.c b/gcc/config/i386/i386-options.c
index 53bd55a12e3..53794b13fc5 100644
--- a/gcc/config/i386/i386-options.c
+++ b/gcc/config/i386/i386-options.c
@@ -406,7 +406,8 @@ ix86_target_string (HOST_WIDE_INT isa, HOST_WIDE_INT isa2,
/* Additional flag options. */
static struct ix86_target_opts flag2_opts[] =
{
- { "-mgeneral-regs-only", OPTION_MASK_GENERAL_REGS_ONLY }
+ { "-mgeneral-regs-only", OPTION_MASK_GENERAL_REGS_ONLY },
+ { "-mvect-compare-costs", OPTION_MASK_X86_VECT_COMPARE_COSTS }
};
const char *opts[ARRAY_SIZE (isa_opts) + ARRAY_SIZE (isa2_opts)
@@ -1111,6 +1112,10 @@ ix86_valid_target_attribute_inner_p (tree fndecl, tree
args, char *p_strings[],
OPT_mgeneral_regs_only,
OPTION_MASK_GENERAL_REGS_ONLY),
+ IX86_ATTR_IX86_YES ("vect-compare-costs",
+ OPT_mvect_compare_costs,
+ OPTION_MASK_X86_VECT_COMPARE_COSTS),
+
IX86_ATTR_YES ("relax-cmpxchg-loop",
OPT_mrelax_cmpxchg_loop,
MASK_RELAX_CMPXCHG_LOOP),
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index ec155826310..fd471c953c4 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -22833,7 +22833,10 @@ ix86_autovectorize_vector_modes (vector_modes *modes,
bool all)
if (TARGET_SSE2)
modes->safe_push (V4QImode);
- return 0;
+ unsigned int flags = 0;
+ if (TARGET_X86_VECT_COMPARE_COSTS)
+ flags |= VECT_COMPARE_COSTS;
+ return flags;
}
/* Implemenation of targetm.vectorize.get_mask_mode. */
diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt
index e1af3e417b0..80c7a073d07 100644
--- a/gcc/config/i386/i386.opt
+++ b/gcc/config/i386/i386.opt
@@ -1206,3 +1206,8 @@ Support MWAIT and MONITOR built-in functions and code
generation.
mavx512fp16
Target Mask(ISA2_AVX512FP16) Var(ix86_isa_flags2) Save
Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2, AVX512F and
AVX512FP16 built-in functions and code generation.
+
+mvect-compare-costs
+Target Mask(X86_VECT_COMPARE_COSTS) Var(ix86_target_flags) Save
+Tells the loop vectorizer to try all the provided vector lengths and pick the
+one with the lowest cost.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index ca621577432..4ee522b3d66 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -1428,7 +1428,7 @@ See RS/6000 and PowerPC Options.
-malign-data=@var{type} -mstack-protector-guard=@var{guard} @gol
-mstack-protector-guard-reg=@var{reg} @gol
-mstack-protector-guard-offset=@var{offset} @gol
--mstack-protector-guard-symbol=@var{symbol} @gol
+-mstack-protector-guard-symbol=@var{symbol} -mvect-compare-costs@gol
-mgeneral-regs-only -mcall-ms2sysv-xlogues -mrelax-cmpxchg-loop @gol
-mindirect-branch=@var{choice} -mfunction-return=@var{choice} @gol
-mindirect-branch-register -mharden-sls=@var{choice} @gol
@@ -32447,6 +32447,11 @@ Generate code that uses only the general-purpose
registers. This
prevents the compiler from using floating-point, vector, mask and bound
registers.
+@item -mvect-compare-costs
+@opindex mcompare-vect-costs
+Tells the loop vectorizer to try all the vector lengths and pick the one
+with the lowest cost.
+
@item -mrelax-cmpxchg-loop
@opindex mrelax-cmpxchg-loop
Relax cmpxchg loop by emitting an early load and compare before cmpxchg,
--
2.18.1
