https://gcc.gnu.org/g:25d51fb7d098a9ac8880ccb2121d889815680177
commit r15-3364-g25d51fb7d098a9ac8880ccb2121d889815680177
Author: Jakub Jelinek <ja...@redhat.com>
Date: Mon Sep 2 09:44:09 2024 +0200
ranger: Fix up range computation for CLZ [PR116486]
The initial CLZ gimple-range-op.cc implementation handled just the
case where second argument to .CLZ is equal to prec, but in
r15-1014 I've added also handling of the -1 case. As the following
testcase shows, incorrectly though for the case where the first argument
has [0,0] range. If the second argument is prec, then the result should
be [prec,prec] and that was handled correctly, but when the second argument
is -1, the result should be [-1,-1] but instead it was incorrectly computed
as [prec-1,prec-1] (when second argument is prec, mini is 0 and maxi is
prec, while when second argument is -1, mini is -1 and maxi is prec-1).
Fixed thusly (the actual handling is then similar to the CTZ [0,0] case).
2024-09-02 Jakub Jelinek <ja...@redhat.com>
PR middle-end/116486
* gimple-range-op.cc (cfn_clz::fold_range): If lh is [0,0]
and mini is -1, return [-1,-1] range rather than [prec-1,prec-1].
* gcc.dg/bitint-109.c: New test.
Diff:
---
gcc/gimple-range-op.cc | 6 ++++--
gcc/testsuite/gcc.dg/bitint-109.c | 25 +++++++++++++++++++++++++
2 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/gcc/gimple-range-op.cc b/gcc/gimple-range-op.cc
index d1c527191f4a..68a7df8d01bc 100644
--- a/gcc/gimple-range-op.cc
+++ b/gcc/gimple-range-op.cc
@@ -972,8 +972,10 @@ cfn_clz::fold_range (irange &r, tree type, const irange
&lh,
{
// If CLZ_DEFINED_VALUE_AT_ZERO is 2 with VALUE of prec,
// return [prec, prec] or [-1, -1], otherwise ignore the range.
- if (maxi == prec || mini == -1)
- mini = maxi;
+ if (maxi == prec)
+ mini = prec;
+ else if (mini == -1)
+ maxi = -1;
}
else if (mini >= 0)
mini = newmini;
diff --git a/gcc/testsuite/gcc.dg/bitint-109.c
b/gcc/testsuite/gcc.dg/bitint-109.c
new file mode 100644
index 000000000000..84c4314cdf9d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/bitint-109.c
@@ -0,0 +1,25 @@
+/* PR middle-end/116486 */
+/* { dg-do run { target bitint } } */
+/* { dg-options "-O2 -fno-tree-ccp" } */
+
+unsigned u;
+
+#if __BITINT_MAXWIDTH__ >= 129
+#define N 0x100000000000000000000000000000000uwb
+#else
+#define N 0xffffffffffffffffuwb
+#endif
+
+int
+foo (void)
+{
+ return __builtin_stdc_first_leading_one (u / N);
+}
+
+int
+main ()
+{
+ int x = foo ();
+ if (x)
+ __builtin_abort ();
+}
