On October 16, 2020 8:46:39 PM GMT+02:00, Martin Jambor <mjam...@suse.cz> wrote:
>Hi,
>
>in PR 97456, IPA-SRA triggers a bug in tree-complex.c where it
>converts:
>
> <bb 2>
> a$_M_value_21 = COMPLEX_EXPR <ISRA.18_10(D), ISRA.18_10(D)>;
>
>(where ISRA.18 is IPA-SRA created PARM_DECL with DECL_IGNORED_P set,
>which is why it only happens with IPA-SRA) into:
>
> <bb 2>
>a$_M_value_21 = COMPLEX_EXPR <a$_M_value$real_10(D),
>a$_M_value$real_10(D)>;
>
>i.e. it replaces two uses of the parameter default-def with two
>uninitialized default-defs of a new variable - all in hope to produce
>code with better debug info.
>
>This patch fixes it by avoiding the transform when the SSA_NAME to be
>replaced is a default definition. Bootstrapped and tested on
>x86_64-linux. OK for trunk and the gcc-10 branch?
It's never OK to replace SSA_NAME_VAR of a default Def so may I suggest to put
this restriction first, independent of any other predicate?
Ok with that change. Thanks,
Richard.
>Thanks,
>
>Martin
>
>
>gcc/ChangeLog:
>
>2020-10-16 Martin Jambor <mjam...@suse.cz>
>
> PR tree-optimization/97456
> * tree-complex.c (set_component_ssa_name): Do not replace ignored decl
> default definitions with new component vars. Reorder if conditions.
>
>gcc/testsuite/ChangeLog:
>
>2020-10-16 Martin Jambor <mjam...@suse.cz>
>
> PR tree-optimization/97456
> * gcc.dg/tree-ssa/pr97456.c: New test.
>---
> gcc/testsuite/gcc.dg/tree-ssa/pr97456.c | 40 +++++++++++++++++++++++++
> gcc/tree-complex.c | 6 ++--
> 2 files changed, 44 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr97456.c
>
>diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr97456.c
>b/gcc/testsuite/gcc.dg/tree-ssa/pr97456.c
>new file mode 100644
>index 00000000000..5171c9b4577
>--- /dev/null
>+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr97456.c
>@@ -0,0 +1,40 @@
>+/* { dg-do run } */
>+/* { dg-options "-O2 -fwhole-program" } */
>+
>+
>+float val2 = 1.710780f;
>+float val3;
>+volatile float vf;
>+
>+int __attribute__((noipa))
>+get_bool (void)
>+{
>+ return 1;
>+}
>+
>+int __attribute__((noinline))
>+wrong (float *pos)
>+{
>+ _Complex float a;
>+
>+ __real__ a = *pos;
>+ __imag__ a = *pos;
>+
>+ _Complex float b = 0 + 0i;
>+
>+ b = b + a;
>+
>+ if (b == 0.0f)
>+ return 1;
>+
>+ vf = __imag__ b;
>+ return 0;
>+}
>+
>+int main(int argc, char **argv) {
>+ float val = get_bool () == 1 ? val2 : val3;
>+
>+ if ((wrong(&val), wrong(&val)))
>+ __builtin_abort ();
>+ return 0;
>+}
>diff --git a/gcc/tree-complex.c b/gcc/tree-complex.c
>index 2e54bbb917c..71ad7c18523 100644
>--- a/gcc/tree-complex.c
>+++ b/gcc/tree-complex.c
>@@ -570,8 +570,10 @@ set_component_ssa_name (tree ssa_name, bool
>imag_p, tree value)
> /* Replace an anonymous base value with the variable from cvc_lookup.
> This should result in better debug info. */
> if (SSA_NAME_VAR (ssa_name)
>- && (!SSA_NAME_VAR (value) || DECL_IGNORED_P (SSA_NAME_VAR (value)))
>- && !DECL_IGNORED_P (SSA_NAME_VAR (ssa_name)))
>+ && !DECL_IGNORED_P (SSA_NAME_VAR (ssa_name))
>+ && (!SSA_NAME_VAR (value)
>+ || (DECL_IGNORED_P (SSA_NAME_VAR (value))
>+ && !SSA_NAME_IS_DEFAULT_DEF (value))))
> {
> comp = get_component_var (SSA_NAME_VAR (ssa_name), imag_p);
> replace_ssa_name_symbol (value, comp);
