https://gcc.gnu.org/g:696d8b9bf3f0ea60da0c24361dc5fe559f97ab77
commit r15-2379-g696d8b9bf3f0ea60da0c24361dc5fe559f97ab77
Author: Pan Li <pan2...@intel.com>
Date: Sat Jul 27 11:29:42 2024 +0800
Widening-Mul: Try .SAT_SUB for PLUS_EXPR when one op is IMM
After add the matching for .SAT_SUB when one op is IMM, there
will be a new root PLUS_EXPR for the .SAT_SUB pattern. For example,
Form 3:
#define DEF_SAT_U_SUB_IMM_FMT_3(T, IMM) \
T __attribute__((noinline)) \
sat_u_sub_imm##IMM##_##T##_fmt_3 (T x) \
{ \
return x >= IMM ? x - IMM : 0; \
}
DEF_SAT_U_SUB_IMM_FMT_3(uint64_t, 11)
And then we will have gimple before widening-mul as below. Thus, try
the .SAT_SUB for the PLUS_EXPR.
4 │ __attribute__((noinline))
5 │ uint64_t sat_u_sub_imm11_uint64_t_fmt_3 (uint64_t x)
6 │ {
7 │ long unsigned int _1;
8 │ uint64_t _3;
9 │
10 │ <bb 2> [local count: 1073741824]:
11 │ _1 = MAX_EXPR <x_2(D), 11>;
12 │ _3 = _1 + 18446744073709551605;
13 │ return _3;
14 │
15 │ }
The below test suites are passed for this patch.
1. The rv64gcv fully regression tests.
2. The x86 bootstrap tests.
3. The x86 fully regression tests.
gcc/ChangeLog:
* tree-ssa-math-opts.cc (math_opts_dom_walker::after_dom_children):
Try .SAT_SUB for PLUS_EXPR case.
Signed-off-by: Pan Li <pan2...@intel.com>
Diff:
---
gcc/tree-ssa-math-opts.cc | 1 +
1 file changed, 1 insertion(+)
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index ac86be8eb947..8d96a4c964b3 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -6129,6 +6129,7 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
case PLUS_EXPR:
match_unsigned_saturation_add (&gsi, as_a<gassign *> (stmt));
+ match_unsigned_saturation_sub (&gsi, as_a<gassign *> (stmt));
/* fall-through */
case MINUS_EXPR:
if (!convert_plusminus_to_widen (&gsi, stmt, code))
