Hi,
When using pack or unpack in the simplification of a vector constructor
we must make sure that the original BIT_FIELD_REF was no sign-changing
nop conversion. If it was we cannot safely pack/unpack as that would
skip sign or zero extensions. This patch adds useless_type_conversion_p
to both paths.
Bootstrapped and regtested on x86 and power10. On power10 I surprisingly
saw one algol68 failure with the patch but that can only be unrelated and due
to the build environment. Re-testing in progress.
Regtested on riscv64 and aarch64, and loongarch64 via qemu.
I tried coming up with an x86 test case but failed. Suggestions welcome.
Regards
Robin
PR tree-optimization/123117
gcc/ChangeLog:
* tree-ssa-forwprop.cc (simplify_vector_constructor):
Check if we had a nop conversion and don't use pack/unpack in
that case.
gcc/testsuite/ChangeLog:
* gcc.target/loongarch/vector/lsx/pr123117.c: New test.
---
.../gcc.target/loongarch/vector/lsx/pr123117.c | 17 +++++++++++++++++
gcc/tree-ssa-forwprop.cc | 12 ++++++++++++
2 files changed, 29 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/loongarch/vector/lsx/pr123117.c
diff --git a/gcc/testsuite/gcc.target/loongarch/vector/lsx/pr123117.c
b/gcc/testsuite/gcc.target/loongarch/vector/lsx/pr123117.c
new file mode 100644
index 00000000000..e16a7204ef4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/vector/lsx/pr123117.c
@@ -0,0 +1,17 @@
+/* { dg-do run } */
+/* { dg-options "-mlsx -DARCH_LOONGARCH64 -O1 -static" } */
+
+#define BS_VEC(type, num) type __attribute__((vector_size(num * sizeof(type))))
+#define T BS_VEC(unsigned, 4)
+
+int main ()
+{
+ BS_VEC(long int, 2) BS_VAR_0[1];
+ BS_VEC(int, 4) tt = (BS_VEC(int, 4)){0x9e47d3d2, 0, 0, 0};
+ asm("":"+f"(tt));
+ BS_VEC(unsigned int, 2) SHUF = __builtin_shufflevector((T)tt, (T)tt, 0, 1);
+ BS_VAR_0[0] = __builtin_convertvector(SHUF, BS_VEC(long int, 2));
+
+ if (BS_VAR_0[0][0] != 0x000000009e47d3d2)
+ __builtin_abort ();
+}
diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
index 2200fc04918..17bfa2a99dc 100644
--- a/gcc/tree-ssa-forwprop.cc
+++ b/gcc/tree-ssa-forwprop.cc
@@ -3848,6 +3848,7 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi)
orig[0] = NULL;
orig[1] = NULL;
+ tree orig_elem_type[2] = {};
conv_code = ERROR_MARK;
bool maybe_ident = true;
bool maybe_blend[2] = { true, true };
@@ -3902,6 +3903,11 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi)
if (j < 2)
{
orig[j] = ref;
+ /* Track what element type was actually extracted (which may
+ differ in signedness from the vector's element type due to
+ tree_nop_conversion_p). */
+ if (!orig_elem_type[j])
+ orig_elem_type[j] = TREE_TYPE (op1);
if (elem != i || j != 0)
maybe_ident = false;
if (elem != i)
@@ -4011,6 +4017,9 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi)
if (CONVERT_EXPR_CODE_P (conv_code)
&& (2 * TYPE_PRECISION (TREE_TYPE (TREE_TYPE (orig[0])))
== TYPE_PRECISION (TREE_TYPE (type)))
+ && orig_elem_type[0]
+ && useless_type_conversion_p (orig_elem_type[0],
+ TREE_TYPE (type))
&& mode_for_vector (as_a <scalar_mode>
(TYPE_MODE (TREE_TYPE (TREE_TYPE (orig[0])))),
nelts * 2).exists ()
@@ -4050,6 +4059,9 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi)
else if (CONVERT_EXPR_CODE_P (conv_code)
&& (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (orig[0])))
== 2 * TYPE_PRECISION (TREE_TYPE (type)))
+ && orig_elem_type[0]
+ && useless_type_conversion_p (orig_elem_type[0],
+ TREE_TYPE (type))
&& mode_for_vector (as_a <scalar_mode>
(TYPE_MODE
(TREE_TYPE (TREE_TYPE (orig[0])))),
--
2.51.1
