https://gcc.gnu.org/g:6ce0821aa5ad174979d5fc15db606810b644c8eb
commit 6ce0821aa5ad174979d5fc15db606810b644c8eb
Author: Jin Ma <ji...@linux.alibaba.com>
Date: Sat Jun 28 19:55:00 2025 +0800
RISC-V: Refactor the function bitmap_union_of_preds_with_entry
The current implementation of this function is somewhat difficult to
understand, as it uses a direct break statement within the for loop,
rendering the loop meaningless. Additionally, during the Coverity check
on the for loop, a warning appeared: "unreachable: Since the loop
increment ix++; is unreachable, the loop body will never execute more
than once." Therefore, I have made some simple refactoring to address
these issues.
gcc/ChangeLog:
* config/riscv/riscv-vsetvl.cc (bitmap_union_of_preds_with_entry):
Refactor.
Signed-off-by: Jin Ma <ji...@linux.alibaba.com>
(cherry picked from commit 2609a7a5971aa8a2ef1bafbf5581dcabd68a466e)
Diff:
---
gcc/config/riscv/riscv-vsetvl.cc | 41 +++++++++++++++++++---------------------
1 file changed, 19 insertions(+), 22 deletions(-)
diff --git a/gcc/config/riscv/riscv-vsetvl.cc b/gcc/config/riscv/riscv-vsetvl.cc
index 4891b6c95e85..4fe0ae6d97b7 100644
--- a/gcc/config/riscv/riscv-vsetvl.cc
+++ b/gcc/config/riscv/riscv-vsetvl.cc
@@ -100,31 +100,28 @@ using namespace riscv_vector;
static void
bitmap_union_of_preds_with_entry (sbitmap dst, sbitmap *src, basic_block b)
{
- unsigned int set_size = dst->size;
- edge e;
- unsigned ix;
-
- for (ix = 0; ix < EDGE_COUNT (b->preds); ix++)
+ /* Handle case with no predecessors (including ENTRY block). */
+ if (EDGE_COUNT (b->preds) == 0)
{
- e = EDGE_PRED (b, ix);
- bitmap_copy (dst, src[e->src->index]);
- break;
+ bitmap_clear (dst);
+ return;
}
- if (ix == EDGE_COUNT (b->preds))
- bitmap_clear (dst);
- else
- for (ix++; ix < EDGE_COUNT (b->preds); ix++)
- {
- unsigned int i;
- SBITMAP_ELT_TYPE *p, *r;
-
- e = EDGE_PRED (b, ix);
- p = src[e->src->index]->elms;
- r = dst->elms;
- for (i = 0; i < set_size; i++)
- *r++ |= *p++;
- }
+ edge e;
+ edge_iterator ei;
+ /* Union remaining predecessors' bitmaps. */
+ FOR_EACH_EDGE (e, ei, b->preds)
+ {
+ /* Initialize with first predecessor's bitmap. */
+ if (ei.index == 0)
+ {
+ bitmap_copy (dst, src[e->src->index]);
+ continue;
+ }
+
+ /* Perform bitmap OR operation element-wise. */
+ bitmap_ior (dst, dst, src[e->src->index]);
+ }
}
/* Compute the reaching definition in and out based on the gen and KILL
