OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Handle a_2= &b properly in range calculations.

Browse Source 
when processing assignments, we were using the type of b instead of type
of &b when computing a range.  This was usually filtered out by FRE.
turning it off exposed it.

	gcc/
	PR tree-optimization/97520
	* gimple-range.cc (range_of_non_trivial_assignment): Handle x = &a
	by returning a non-zero range.
	gcc/testsuite/
	* gcc.dg/pr97520.c: New.
This commit is contained in:
Andrew MacLeod 2020-10-21 20:11:16 -04:00
parent 0f41b5e02f
commit 966fdb2e12
2 changed files with 34 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
gcc/gimple-range.cc
View File

@ -446,17 +446,31 @@ gimple_ranger::range_of_non_trivial_assignment (irange &r, gimple *stmt)
return false;
tree base = gimple_range_base_of_assignment (stmt);
if (base && TREE_CODE (base) == MEM_REF
&& TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
if (base)
{
int_range_max range1;
tree ssa = TREE_OPERAND (base, 0);
if (range_of_expr (range1, ssa, stmt))
if (TREE_CODE (base) == MEM_REF)
{
tree type = TREE_TYPE (ssa);
range_operator *op = range_op_handler (POINTER_PLUS_EXPR, type);
int_range<2> offset (TREE_OPERAND (base, 1), TREE_OPERAND (base, 1));
op->fold_range (r, type, range1, offset);
if (TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
{
int_range_max range1;
tree ssa = TREE_OPERAND (base, 0);
if (range_of_expr (range1, ssa, stmt))
{
tree type = TREE_TYPE (ssa);
range_operator *op = range_op_handler (POINTER_PLUS_EXPR,
type);
int_range<2> offset (TREE_OPERAND (base, 1),
TREE_OPERAND (base, 1));
op->fold_range (r, type, range1, offset);
return true;
}
}
return false;
}
if (gimple_assign_rhs_code (stmt) == ADDR_EXPR)
{
// Handle "= &a" and return non-zero.
r = range_nonzero (TREE_TYPE (gimple_assign_rhs1 (stmt)));
return true;
}
}

11
gcc/testsuite/gcc.dg/pr97520.c Normal file
View File

@ -0,0 +1,11 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fno-tree-fre" } */
char a;
void b() {
char *c[5];
char *d = &a;
&d;
*(c[4] = d);
}
int main() { return 0; }