Hi,
On Wed, Apr 08 2020, Richard Biener wrote:
> On Tue, 7 Apr 2020, Richard Biener wrote:
>
>> On April 7, 2020 6:25:26 PM GMT+02:00, Martin Jambor <mjam...@suse.cz> wrote:
>> >Hi,
>> >
>> >On Tue, Apr 07 2020, Richard Biener wrote:
>> >> On Tue, 7 Apr 2020, Martin Jambor wrote:
>> >>
>> >>> Hi,
>> >>>
>> >>> when sra_modify_expr is invoked on an expression that modifies only
>> >>> part of the underlying replacement, such as a BIT_FIELD_REF on a LHS
>> >>> of an assignment and the SRA replacement's type is not compatible
>> >with
>> >>> what is being replaced (0th operand of the B_F_R in the above
>> >>> example), it does not work properly, basically throwing away the
>> >partd
>> >>> of the expr that should have stayed intact.
>> >>>
>> >>> This is fixed in two ways. For BIT_FIELD_REFs, which operate on the
>> >>> binary image of the replacement (and so in a way serve as a
>> >>> VIEW_CONVERT_EXPR) we just do not bother with convertsing. For
>> >>> REALPART_EXPRs and IMAGPART_EXPRs, we insert a VIEW_CONVERT_EXPR
>> >under
>> >>> the complex partial access expression, which is OK even in a LHS of
>> >an
>> >>> assignment (and other write contexts) because in those cases the
>> >>> replacement is not going to be a giple register anyway.
>> >>>
>> >>> The testcase for handling REALPART_EXPR and IMAGPART_EXPR is a bit
>> >>> fragile because SRA prefers complex and vector types over anything
>> >else
>> >>> (and in between the two it decides based on TYPE_UID which in my
>> >testing
>> >>> today always preferred complex types) and even when GIMPLE is wrong
>> >I
>> >>> often still did not get failing runs, so I only run it at -O1 (which
>> >is
>> >>> the only level where the the test fails for me).
>> >>>
>> >>> Bootstrapped and tested on x86_64-linux, bootstrap and testing on
>> >>> i686-linux and aarch64-linux underway.
>> >>>
>> >>> OK for trunk (and subsequently for release branches) if it passes?
>> >>
>> >> OK.
>> >
>> >I must have been already half asleep when writing that it passed
>> >testing. It did not, testsuite/gcc.c-torture/compile/pr42196-3.c fails
>> >even on x86_64, because fwprop happily combines
>> >
>> > u$ci_10 = MEM[(union U *)&u];
>> >
>> >and
>> >
>> > f1_6 = IMAGPART_EXPR <VIEW_CONVERT_EXPR<complex float>(u$ci_10)>;
>> >
>> >into
>> >
>> > f1_6 = IMAGPART_EXPR <MEM[(union U *)&u]>;
>> >
>> >and the gimple verifier of course does not like that. I'll have a look
>> >at that tomorrow.
>>
>> Ah, that might be a genuine fwprop bug.
>
> On a second thought
>
> f1_6 = IMAGPART_EXPR <VIEW_CONVERT_EXPR<complex float>(u$ci_10)>;
>
> shouldn't be valid GIMPLE since 'complex float' is a register type
> and thus it should have been
>
> _11 = VIEW_CONVERT_EXPR<complex float>(u$ci_10);
> f1_6 = IMAGPART_EXPR <_11>;
>
OK, the newest version of the patch below is careful to do that if the
replacement is going to be a gimple_register,
> now it's a bit of a grey area since a load like
>
> f1_6 = IMAGPART_EXPR <VIEW_CONVERT_EXPR<complex float>(u);
>
> is valid (we don't want to force a whole _Complex load here).
and the above for non-gimple-registers.
>
> For example in VN
>
> f1_6 = IMAGPART_EXPR <VIEW_CONVERT_EXPR<complex float>(u$ci_10)>;
>
> goes through the load machinery.
>
> So let's say the IL is undesirable at least.
>
> The following fixes the forwprop laziness, please include it in the
> patch so it gets cherry-picked for backports.
I added it to the modified patch, it was still necessary. The version
below has passed bootstrap and testing on x86-64-linux and aarch64-linux
(and I have double checked!) and bootstrap on i686-linux, testing on the
32-bit platform is still ongoing. OK if it passes there too?
Thanks,
Martin
sra: Fix sra_modify_expr handling of partial writes (PR 94482)
when sra_modify_expr is invoked on an expression that modifies only
part of the underlying replacement, such as a BIT_FIELD_REF on a LHS
of an assignment and the SRA replacement's type is not compatible with
what is being replaced (0th operand of the B_F_R in the above
example), it does not work properly, basically throwing away the partd
of the expr that should have stayed intact.
This is fixed in two ways. For BIT_FIELD_REFs, which operate on the
binary image of the replacement (and so in a way serve as a
VIEW_CONVERT_EXPR) we just do not bother with convertsing. For
REALPART_EXPRs and IMAGPART_EXPRs, if the replacement is not a
register, we insert a VIEW_CONVERT_EXPR under
the complex partial access expression, which is always OK, for loads
from registers we take the extra step of converting it to a temporary.
This revealed a bug in fwprop which is fixed with the hunk from Richi.
The testcase for handling REALPART_EXPR and IMAGPART_EXPR is a bit
fragile because SRA prefers complex and vector types over anything
else (and in between the two it decides based on TYPE_UID which in my
testing today always preferred complex types) and so I only run it at
-O1 (which is the only level where the the test fails for me).
2020-04-08 Martin Jambor <mjam...@suse.cz>
Richard Biener <rguent...@suse.de>
PR tree-optimization/94482
* tree-sra.c (create_access_replacement): Dump new replacement with
TDF_UID.
(sra_modify_expr): Fix handling of cases when the original EXPR writes
to only part of the replacement.
* tree-ssa-forwprop.c (pass_forwprop::execute): Properly verify
the first operand of combinations into REAL/IMAGPART_EXPR and
BIT_FIELD_REF.
testsuite/
* gcc.dg/torture/pr94482.c: New test.
* gcc.dg/tree-ssa/pr94482-2.c: Likewise.
---
gcc/ChangeLog | 12 ++++++
gcc/testsuite/ChangeLog | 6 +++
gcc/testsuite/gcc.dg/torture/pr94482.c | 34 +++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr94482-2.c | 50 +++++++++++++++++++++++
gcc/tree-sra.c | 31 ++++++++++++--
gcc/tree-ssa-forwprop.c | 6 ++-
6 files changed, 133 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr94482.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr94482-2.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e10fb251c16..675ac2a4b6a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2020-04-08 Martin Jambor <mjam...@suse.cz>
+ Richard Biener <rguent...@suse.de>
+
+ PR tree-optimization/94482
+ * tree-sra.c (create_access_replacement): Dump new replacement with
+ TDF_UID.
+ (sra_modify_expr): Fix handling of cases when the original EXPR writes
+ to only part of the replacement.
+ * tree-ssa-forwprop.c (pass_forwprop::execute): Properly verify
+ the first operand of combinations into REAL/IMAGPART_EXPR and
+ BIT_FIELD_REF.
+
2020-04-05 Zachary Spytz <zsp...@gmail.com>
* extend.texi: Add free to list of ISO C90 functions that
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 88bab5d3d19..b0d94b5394e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2020-04-08 Martin Jambor <mjam...@suse.cz>
+
+ PR tree-optimization/94482
+ * gcc.dg/torture/pr94482.c: New test.
+ * gcc.dg/tree-ssa/pr94482-2.c: Likewise.
+
2020-04-05 Iain Sandoe <i...@sandoe.co.uk>
* g++.dg/coroutines/torture/co-await-14-template-traits.C: Rename...
diff --git a/gcc/testsuite/gcc.dg/torture/pr94482.c
b/gcc/testsuite/gcc.dg/torture/pr94482.c
new file mode 100644
index 00000000000..5bb19e745c2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr94482.c
@@ -0,0 +1,34 @@
+/* { dg-do run } */
+
+typedef unsigned V __attribute__ ((__vector_size__ (16)));
+union U
+{
+ V j;
+ unsigned long long i __attribute__ ((__vector_size__ (16)));
+};
+
+static inline __attribute__((always_inline)) V
+foo (unsigned long long a)
+{
+ union U z = { .j = (V) {} };
+ for (unsigned long i = 0; i < 1; i++)
+ z.i[i] = a;
+ return z.j;
+}
+
+static inline __attribute__((always_inline)) V
+bar (V a, unsigned long long i, int q)
+{
+ union U z = { .j = a };
+ z.i[q] = i;
+ return z.j;
+}
+
+int
+main ()
+{
+ union U z = { .j = bar (foo (1729), 2, 1) };
+ if (z.i[0] != 1729)
+ __builtin_abort ();
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr94482-2.c
b/gcc/testsuite/gcc.dg/tree-ssa/pr94482-2.c
new file mode 100644
index 00000000000..fcac9d5e439
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr94482-2.c
@@ -0,0 +1,50 @@
+/* { dg-do run } */
+/* { dg-options "-O1" } */
+
+typedef unsigned long V __attribute__ ((__vector_size__ (8)));
+typedef _Complex int Ci;
+typedef _Complex float Cf;
+
+union U
+{
+ Ci ci;
+ Cf cf;
+};
+
+volatile Ci vgi;
+
+Cf foo (Cf c)
+{
+ __real c = 0x1ffp10;
+ return c;
+}
+
+Ci ioo (Ci c)
+{
+ __real c = 50;
+ return c;
+}
+
+
+int main (int argc, char *argv[])
+{
+ union U u;
+
+ __real u.ci = 500;
+ __imag u.ci = 1000;
+ vgi = u.ci;
+
+ u.ci = ioo (u.ci);
+ __imag u.ci = 100;
+
+ if (__real u.ci != 50 || __imag u.ci != 100)
+ __builtin_abort();
+
+ u.cf = foo (u.cf);
+ __imag u.cf = 0x1p3;
+
+ if (__real u.cf != 0x1ffp10 || __imag u.cf != 0x1p3)
+ __builtin_abort();
+
+ return 0;
+}
diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index b2056b58750..84c113c403c 100644
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -2257,7 +2257,7 @@ create_access_replacement (struct access *access, tree
reg_type = NULL_TREE)
print_generic_expr (dump_file, access->base);
fprintf (dump_file, " offset: %u, size: %u: ",
(unsigned) access->offset, (unsigned) access->size);
- print_generic_expr (dump_file, repl);
+ print_generic_expr (dump_file, repl, TDF_UID);
fprintf (dump_file, "\n");
}
}
@@ -3698,6 +3698,7 @@ sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi,
bool write)
location_t loc;
struct access *access;
tree type, bfr, orig_expr;
+ bool partial_cplx_access = false;
if (TREE_CODE (*expr) == BIT_FIELD_REF)
{
@@ -3708,7 +3709,10 @@ sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi,
bool write)
bfr = NULL_TREE;
if (TREE_CODE (*expr) == REALPART_EXPR || TREE_CODE (*expr) == IMAGPART_EXPR)
- expr = &TREE_OPERAND (*expr, 0);
+ {
+ expr = &TREE_OPERAND (*expr, 0);
+ partial_cplx_access = true;
+ }
access = get_access_for_expr (*expr);
if (!access)
return false;
@@ -3736,13 +3740,32 @@ sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi,
bool write)
be accessed as a different type too, potentially creating a need for
type conversion (see PR42196) and when scalarized unions are involved
in assembler statements (see PR42398). */
- if (!useless_type_conversion_p (type, access->type))
+ if (!bfr && !useless_type_conversion_p (type, access->type))
{
tree ref;
ref = build_ref_for_model (loc, orig_expr, 0, access, gsi, false);
- if (write)
+ if (partial_cplx_access)
+ {
+ /* VIEW_CONVERT_EXPRs in partial complex access are always fine in
+ the case of a write because in such case the replacement cannot
+ be a gimple register. In the case of a load, we have to
+ differentiate in between a register an non-register
+ replacement. */
+ tree t = build1 (VIEW_CONVERT_EXPR, type, repl);
+ gcc_checking_assert (!write || access->grp_partial_lhs);
+ if (!access->grp_partial_lhs)
+ {
+ tree tmp = make_ssa_name (type);
+ gassign *stmt = gimple_build_assign (tmp, t);
+ /* This is always a read. */
+ gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
+ t = tmp;
+ }
+ *expr = t;
+ }
+ else if (write)
{
gassign *stmt;
diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index e7eaa18ccad..3d8acf7eb03 100644
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -2815,7 +2815,8 @@ pass_forwprop::execute (function *fun)
continue;
if (!is_gimple_assign (use_stmt)
|| (gimple_assign_rhs_code (use_stmt) != REALPART_EXPR
- && gimple_assign_rhs_code (use_stmt) !=
IMAGPART_EXPR))
+ && gimple_assign_rhs_code (use_stmt) != IMAGPART_EXPR)
+ || TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 0) != lhs)
{
rewrite = false;
break;
@@ -2877,7 +2878,8 @@ pass_forwprop::execute (function *fun)
if (is_gimple_debug (use_stmt))
continue;
if (!is_gimple_assign (use_stmt)
- || gimple_assign_rhs_code (use_stmt) != BIT_FIELD_REF)
+ || gimple_assign_rhs_code (use_stmt) != BIT_FIELD_REF
+ || TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 0) != lhs)
{
rewrite = false;
break;
--
2.26.0
