The problem here is that VRP cannot figure out isize could not be 0
due to using integer_zerop. This patch removes the use of integer_zerop
and instead checks for 0 directly after converting the tree to
an unsigned HOST_WIDE_INT. This allows VRP to figure out isize is not 0
and `isize - 1` will always be >= 0.
This patch is just to avoid the warning that GCC could produce sometimes
and does not change any code generation or even VRP.
OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
gcc/ChangeLog:
* tree-ssa-forwprop.cc (simplify_builtin_call): Check
against 0 instead of calling integer_zerop.
---
gcc/tree-ssa-forwprop.cc | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
index 06f19868ade..0326e6733e8 100644
--- a/gcc/tree-ssa-forwprop.cc
+++ b/gcc/tree-ssa-forwprop.cc
@@ -1231,14 +1231,14 @@ simplify_builtin_call (gimple_stmt_iterator *gsi_p,
tree callee2)
tree size = gimple_call_arg (stmt2, 2);
/* Size must be a constant which is <= UNITS_PER_WORD and
<= the string length. */
- if (TREE_CODE (size) != INTEGER_CST || integer_zerop (size))
+ if (TREE_CODE (size) != INTEGER_CST)
break;
if (!tree_fits_uhwi_p (size))
break;
unsigned HOST_WIDE_INT sz = tree_to_uhwi (size);
- if (sz > UNITS_PER_WORD || sz >= slen)
+ if (sz == 0 || sz > UNITS_PER_WORD || sz >= slen)
break;
tree ch = gimple_call_arg (stmt2, 1);
--
2.31.1
