https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127879
Bug ID: 127879
Summary: Improve fold_using_range::range_from_readonly_var for
STRING_CSTs and RAW_DATA_CST
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
Target Milestone: ---
const unsigned char a[] = { 100, 108, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,
0, 24, 18, 35, 98 };
const unsigned char b[] = { 100, 108, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57,
0, 24, 18, 35, 98 };
const struct { int a; unsigned char b; } c[] = { { 0, 100 }, { 0, 108 }, { 0,
48 }, { 0, 49 }, { 0, 50 }, { 0, 51 },
{ 0, 52 }, { 0, 53 }, { 0, 54
}, { 0, 55 }, { 0, 56 }, { 0, 57 },
{ 0, 0 }, { 0, 24 }, { 0, 18
}, { 0, 35 }, { 0, 98 } };
int
foo (int x)
{
if (x < 2 || x >= 12)
return -1;
if (a[x] >= 48 && a[x] <= 57)
return 1;
return 0;
}
int
bar (int x)
{
if (x < 2 || x >= 220)
return -1;
if (b[x] >= 48 && b[x] <= 57)
return 1;
return 0;
}
int
baz (int x)
{
if (x < 2 || x >= 12)
return -1;
if (c[x].b >= 48 && c[x].b <= 57)
return 1;
return 0;
}
with -O2 --param vrp-cstload-limit=255 optimizes just baz into return x + 2U >=
14U ? -1 : 1; and doesn't optimize foo nor bar.
For foo, braced_list_to_string optimizes the CONSTRUCTOR into a STRING_CST
(and, it can appear both as toplevel thing from fold_ctor_reference or just its
part), for bar it gives up on RAW_DATA_CST.
Will try to handle this tomorrow.
