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* Re: [PATCH] tree-optimization/111779 - Handle some BIT_FIELD_REFs in SRA
@ 2023-10-12 11:44 Richard Biener
  2023-10-12 12:01 ` Andre Vehreschild
  0 siblings, 1 reply; 3+ messages in thread
From: Richard Biener @ 2023-10-12 11:44 UTC (permalink / raw)
  To: gcc-patches; +Cc: Martin Jambor, fortran

On Thu, 12 Oct 2023, Richard Biener wrote:

> The following handles byte-aligned, power-of-two and byte-multiple
> sized BIT_FIELD_REF reads in SRA.  In particular this should cover
> BIT_FIELD_REFs created by optimize_bit_field_compare.
> 
> For gcc.dg/tree-ssa/ssa-dse-26.c we now SRA the BIT_FIELD_REF
> appearing there leading to more DSE, fully eliding the aggregates.
> 
> This results in the same false positive -Wuninitialized as the
> older attempt to remove the folding from optimize_bit_field_compare,
> fixed by initializing part of the aggregate unconditionally.
> 
> Bootstrapped and tested on x86_64-unknown-linux-gnu for all languages.
> 
> Martin is on leave so I'll push this tomorrow unless the Fortran
> folks have objections.

Err, and I forgot that hunk.  It's

diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index 7beefa2e69c..1b8be081a17 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -12015,7 +12015,10 @@ gfc_trans_assignment_1 (gfc_expr * expr1, gfc_expr * expr2, bool init_flag,
 		 && !is_runtime_conformable (expr1, expr2);
 
   /* Only analyze the expressions for coarray properties, when in coarray-lib
-     mode.  */
+     mode.  Avoid false-positive uninitialized diagnostics with initializing
+     the codimension flag unconditionally.  */
+  lhs_caf_attr.codimension = false;
+  rhs_caf_attr.codimension = false;
   if (flag_coarray == GFC_FCOARRAY_LIB)
     {
       lhs_caf_attr = gfc_caf_attr (expr1, false, &lhs_refs_comp);


> Thanks,
> Richard.
> 
> 	PR tree-optimization/111779
> gcc/
> 	* tree-sra.cc (sra_handled_bf_read_p): New function.
> 	(build_access_from_expr_1): Handle some BIT_FIELD_REFs.
> 	(sra_modify_expr): Likewise.
> 	(make_fancy_name_1): Skip over BIT_FIELD_REF.
> 
> gcc/fortran/
> 	* trans-expr.cc (gfc_trans_assignment_1): Initialize
> 	lhs_caf_attr and rhs_caf_attr codimension flag to avoid
> 	false positive -Wuninitialized.
> 
> gcc/testsuite/
> 	* gcc.dg/tree-ssa/ssa-dse-26.c: Adjust for more DSE.
> 	* gcc.dg/vect/vect-pr111779.c: New testcase.
> ---
>  gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c |  4 +-
>  gcc/testsuite/gcc.dg/vect/vect-pr111779.c  | 56 ++++++++++++++++++++++
>  gcc/tree-sra.cc                            | 24 ++++++++--
>  3 files changed, 79 insertions(+), 5 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.dg/vect/vect-pr111779.c
> 
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c
> index e3c33f49ef6..43152de5616 100644
> --- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c
> @@ -31,5 +31,5 @@ constraint_equal (struct constraint a, struct constraint b)
>      && constraint_expr_equal (a.rhs, b.rhs);
>  }
>  
> -/* { dg-final { scan-tree-dump-times "Deleted dead store: x = " 1 "dse1" } } */
> -/* { dg-final { scan-tree-dump-times "Deleted dead store: y = " 1 "dse1" } } */
> +/* { dg-final { scan-tree-dump-times "Deleted dead store: x = " 2 "dse1" } } */
> +/* { dg-final { scan-tree-dump-times "Deleted dead store: y = " 2 "dse1" } } */
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-pr111779.c b/gcc/testsuite/gcc.dg/vect/vect-pr111779.c
> new file mode 100644
> index 00000000000..79b72aebc78
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/vect-pr111779.c
> @@ -0,0 +1,56 @@
> +#include <stdbool.h>
> +#include "tree-vect.h"
> +
> +struct C
> +{
> +    int c;
> +    int d;
> +    bool f :1;
> +    float e;
> +};
> +
> +struct A
> +{
> +  unsigned int a;
> +  unsigned char c1, c2;
> +  bool b1 : 1;
> +  bool b2 : 1;
> +  bool b3 : 1;
> +  struct C b4;
> +};
> +
> +void __attribute__((noipa))
> +foo (const struct A * __restrict x, int y)
> +{
> +  int s = 0, i = 0;
> +  for (i = 0; i < y; ++i)
> +    {
> +      const struct A a = x[i];
> +      s += a.b4.f ? 1 : 0;
> +    }
> +  if (s != 0)
> +    __builtin_abort ();
> +}
> +
> +int
> +main ()
> +{
> +  struct A x[100];
> +  int i;
> +
> +  check_vect ();
> +
> +  __builtin_memset (x, -1, sizeof (x));
> +#pragma GCC novect
> +  for (i = 0; i < 100; i++)
> +    {
> +      x[i].b1 = false;
> +      x[i].b2 = false;
> +      x[i].b3 = false;
> +      x[i].b4.f = false;
> +    }
> +  foo (x, 100);
> +  return 0;
> +}
> +
> +/* { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" { target vect_int } } } */
> diff --git a/gcc/tree-sra.cc b/gcc/tree-sra.cc
> index 56a8ba26135..24d0c20da6a 100644
> --- a/gcc/tree-sra.cc
> +++ b/gcc/tree-sra.cc
> @@ -1113,6 +1113,21 @@ disqualify_base_of_expr (tree t, const char *reason)
>      disqualify_candidate (t, reason);
>  }
>  
> +/* Return true if the BIT_FIELD_REF read EXPR is handled by SRA.  */
> +
> +static bool
> +sra_handled_bf_read_p (tree expr)
> +{
> +  uint64_t size, offset;
> +  if (bit_field_size (expr).is_constant (&size)
> +      && bit_field_offset (expr).is_constant (&offset)
> +      && size % BITS_PER_UNIT == 0
> +      && offset % BITS_PER_UNIT == 0
> +      && pow2p_hwi (size))
> +    return true;
> +  return false;
> +}
> +
>  /* Scan expression EXPR and create access structures for all accesses to
>     candidates for scalarization.  Return the created access or NULL if none is
>     created.  */
> @@ -1123,7 +1138,8 @@ build_access_from_expr_1 (tree expr, gimple *stmt, bool write)
>    struct access *ret = NULL;
>    bool partial_ref;
>  
> -  if (TREE_CODE (expr) == BIT_FIELD_REF
> +  if ((TREE_CODE (expr) == BIT_FIELD_REF
> +       && (write || !sra_handled_bf_read_p (expr)))
>        || TREE_CODE (expr) == IMAGPART_EXPR
>        || TREE_CODE (expr) == REALPART_EXPR)
>      {
> @@ -1170,6 +1186,7 @@ build_access_from_expr_1 (tree expr, gimple *stmt, bool write)
>      case COMPONENT_REF:
>      case ARRAY_REF:
>      case ARRAY_RANGE_REF:
> +    case BIT_FIELD_REF:
>        ret = create_access (expr, stmt, write);
>        break;
>  
> @@ -1549,6 +1566,7 @@ make_fancy_name_1 (tree expr)
>        obstack_grow (&name_obstack, buffer, strlen (buffer));
>        break;
>  
> +    case BIT_FIELD_REF:
>      case ADDR_EXPR:
>        make_fancy_name_1 (TREE_OPERAND (expr, 0));
>        break;
> @@ -1564,7 +1582,6 @@ make_fancy_name_1 (tree expr)
>  	}
>        break;
>  
> -    case BIT_FIELD_REF:
>      case REALPART_EXPR:
>      case IMAGPART_EXPR:
>        gcc_unreachable (); 	/* we treat these as scalars.  */
> @@ -3769,7 +3786,8 @@ sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi, bool write)
>    tree type, bfr, orig_expr;
>    bool partial_cplx_access = false;
>  
> -  if (TREE_CODE (*expr) == BIT_FIELD_REF)
> +  if (TREE_CODE (*expr) == BIT_FIELD_REF
> +      && (write || !sra_handled_bf_read_p (*expr)))
>      {
>        bfr = *expr;
>        expr = &TREE_OPERAND (*expr, 0);
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] tree-optimization/111779 - Handle some BIT_FIELD_REFs in SRA
  2023-10-12 11:44 [PATCH] tree-optimization/111779 - Handle some BIT_FIELD_REFs in SRA Richard Biener
@ 2023-10-12 12:01 ` Andre Vehreschild
  0 siblings, 0 replies; 3+ messages in thread
From: Andre Vehreschild @ 2023-10-12 12:01 UTC (permalink / raw)
  To: Richard Biener; +Cc: gcc-patches, Martin Jambor, fortran

Hi Richard,

being the one who wrote the surrounding code:
The fortran part looks good to me.

Ok for merge from the fortran side.

- Andre

On Thu, 12 Oct 2023 11:44:01 +0000 (UTC)
Richard Biener <rguenther@suse.de> wrote:

> On Thu, 12 Oct 2023, Richard Biener wrote:
>
> > The following handles byte-aligned, power-of-two and byte-multiple
> > sized BIT_FIELD_REF reads in SRA.  In particular this should cover
> > BIT_FIELD_REFs created by optimize_bit_field_compare.
> >
> > For gcc.dg/tree-ssa/ssa-dse-26.c we now SRA the BIT_FIELD_REF
> > appearing there leading to more DSE, fully eliding the aggregates.
> >
> > This results in the same false positive -Wuninitialized as the
> > older attempt to remove the folding from optimize_bit_field_compare,
> > fixed by initializing part of the aggregate unconditionally.
> >
> > Bootstrapped and tested on x86_64-unknown-linux-gnu for all languages.
> >
> > Martin is on leave so I'll push this tomorrow unless the Fortran
> > folks have objections.
>
> Err, and I forgot that hunk.  It's
>
> diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
> index 7beefa2e69c..1b8be081a17 100644
> --- a/gcc/fortran/trans-expr.cc
> +++ b/gcc/fortran/trans-expr.cc
> @@ -12015,7 +12015,10 @@ gfc_trans_assignment_1 (gfc_expr * expr1, gfc_expr *
> expr2, bool init_flag, && !is_runtime_conformable (expr1, expr2);
>
>    /* Only analyze the expressions for coarray properties, when in coarray-lib
> -     mode.  */
> +     mode.  Avoid false-positive uninitialized diagnostics with initializing
> +     the codimension flag unconditionally.  */
> +  lhs_caf_attr.codimension = false;
> +  rhs_caf_attr.codimension = false;
>    if (flag_coarray == GFC_FCOARRAY_LIB)
>      {
>        lhs_caf_attr = gfc_caf_attr (expr1, false, &lhs_refs_comp);
>
>
> > Thanks,
> > Richard.
> >
> > 	PR tree-optimization/111779
> > gcc/
> > 	* tree-sra.cc (sra_handled_bf_read_p): New function.
> > 	(build_access_from_expr_1): Handle some BIT_FIELD_REFs.
> > 	(sra_modify_expr): Likewise.
> > 	(make_fancy_name_1): Skip over BIT_FIELD_REF.
> >
> > gcc/fortran/
> > 	* trans-expr.cc (gfc_trans_assignment_1): Initialize
> > 	lhs_caf_attr and rhs_caf_attr codimension flag to avoid
> > 	false positive -Wuninitialized.
> >
> > gcc/testsuite/
> > 	* gcc.dg/tree-ssa/ssa-dse-26.c: Adjust for more DSE.
> > 	* gcc.dg/vect/vect-pr111779.c: New testcase.
> > ---
> >  gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c |  4 +-
> >  gcc/testsuite/gcc.dg/vect/vect-pr111779.c  | 56 ++++++++++++++++++++++
> >  gcc/tree-sra.cc                            | 24 ++++++++--
> >  3 files changed, 79 insertions(+), 5 deletions(-)
> >  create mode 100644 gcc/testsuite/gcc.dg/vect/vect-pr111779.c
> >
> > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c
> > b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c index e3c33f49ef6..43152de5616
> > 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c
> > +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c
> > @@ -31,5 +31,5 @@ constraint_equal (struct constraint a, struct constraint
> > b) && constraint_expr_equal (a.rhs, b.rhs);
> >  }
> >
> > -/* { dg-final { scan-tree-dump-times "Deleted dead store: x = " 1 "dse1" }
> > } */ -/* { dg-final { scan-tree-dump-times "Deleted dead store: y = " 1
> > "dse1" } } */ +/* { dg-final { scan-tree-dump-times "Deleted dead store: x
> > = " 2 "dse1" } } */ +/* { dg-final { scan-tree-dump-times "Deleted dead
> > store: y = " 2 "dse1" } } */ diff --git
> > a/gcc/testsuite/gcc.dg/vect/vect-pr111779.c
> > b/gcc/testsuite/gcc.dg/vect/vect-pr111779.c new file mode 100644 index
> > 00000000000..79b72aebc78 --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/vect/vect-pr111779.c
> > @@ -0,0 +1,56 @@
> > +#include <stdbool.h>
> > +#include "tree-vect.h"
> > +
> > +struct C
> > +{
> > +    int c;
> > +    int d;
> > +    bool f :1;
> > +    float e;
> > +};
> > +
> > +struct A
> > +{
> > +  unsigned int a;
> > +  unsigned char c1, c2;
> > +  bool b1 : 1;
> > +  bool b2 : 1;
> > +  bool b3 : 1;
> > +  struct C b4;
> > +};
> > +
> > +void __attribute__((noipa))
> > +foo (const struct A * __restrict x, int y)
> > +{
> > +  int s = 0, i = 0;
> > +  for (i = 0; i < y; ++i)
> > +    {
> > +      const struct A a = x[i];
> > +      s += a.b4.f ? 1 : 0;
> > +    }
> > +  if (s != 0)
> > +    __builtin_abort ();
> > +}
> > +
> > +int
> > +main ()
> > +{
> > +  struct A x[100];
> > +  int i;
> > +
> > +  check_vect ();
> > +
> > +  __builtin_memset (x, -1, sizeof (x));
> > +#pragma GCC novect
> > +  for (i = 0; i < 100; i++)
> > +    {
> > +      x[i].b1 = false;
> > +      x[i].b2 = false;
> > +      x[i].b3 = false;
> > +      x[i].b4.f = false;
> > +    }
> > +  foo (x, 100);
> > +  return 0;
> > +}
> > +
> > +/* { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" { target vect_int
> > } } } */ diff --git a/gcc/tree-sra.cc b/gcc/tree-sra.cc
> > index 56a8ba26135..24d0c20da6a 100644
> > --- a/gcc/tree-sra.cc
> > +++ b/gcc/tree-sra.cc
> > @@ -1113,6 +1113,21 @@ disqualify_base_of_expr (tree t, const char *reason)
> >      disqualify_candidate (t, reason);
> >  }
> >
> > +/* Return true if the BIT_FIELD_REF read EXPR is handled by SRA.  */
> > +
> > +static bool
> > +sra_handled_bf_read_p (tree expr)
> > +{
> > +  uint64_t size, offset;
> > +  if (bit_field_size (expr).is_constant (&size)
> > +      && bit_field_offset (expr).is_constant (&offset)
> > +      && size % BITS_PER_UNIT == 0
> > +      && offset % BITS_PER_UNIT == 0
> > +      && pow2p_hwi (size))
> > +    return true;
> > +  return false;
> > +}
> > +
> >  /* Scan expression EXPR and create access structures for all accesses to
> >     candidates for scalarization.  Return the created access or NULL if
> > none is created.  */
> > @@ -1123,7 +1138,8 @@ build_access_from_expr_1 (tree expr, gimple *stmt,
> > bool write) struct access *ret = NULL;
> >    bool partial_ref;
> >
> > -  if (TREE_CODE (expr) == BIT_FIELD_REF
> > +  if ((TREE_CODE (expr) == BIT_FIELD_REF
> > +       && (write || !sra_handled_bf_read_p (expr)))
> >        || TREE_CODE (expr) == IMAGPART_EXPR
> >        || TREE_CODE (expr) == REALPART_EXPR)
> >      {
> > @@ -1170,6 +1186,7 @@ build_access_from_expr_1 (tree expr, gimple *stmt,
> > bool write) case COMPONENT_REF:
> >      case ARRAY_REF:
> >      case ARRAY_RANGE_REF:
> > +    case BIT_FIELD_REF:
> >        ret = create_access (expr, stmt, write);
> >        break;
> >
> > @@ -1549,6 +1566,7 @@ make_fancy_name_1 (tree expr)
> >        obstack_grow (&name_obstack, buffer, strlen (buffer));
> >        break;
> >
> > +    case BIT_FIELD_REF:
> >      case ADDR_EXPR:
> >        make_fancy_name_1 (TREE_OPERAND (expr, 0));
> >        break;
> > @@ -1564,7 +1582,6 @@ make_fancy_name_1 (tree expr)
> >  	}
> >        break;
> >
> > -    case BIT_FIELD_REF:
> >      case REALPART_EXPR:
> >      case IMAGPART_EXPR:
> >        gcc_unreachable (); 	/* we treat these as scalars.  */
> > @@ -3769,7 +3786,8 @@ sra_modify_expr (tree *expr, gimple_stmt_iterator
> > *gsi, bool write) tree type, bfr, orig_expr;
> >    bool partial_cplx_access = false;
> >
> > -  if (TREE_CODE (*expr) == BIT_FIELD_REF)
> > +  if (TREE_CODE (*expr) == BIT_FIELD_REF
> > +      && (write || !sra_handled_bf_read_p (*expr)))
> >      {
> >        bfr = *expr;
> >        expr = &TREE_OPERAND (*expr, 0);
> >
>


--
Andre Vehreschild * Email: vehre ad gmx dot de

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [PATCH] tree-optimization/111779 - Handle some BIT_FIELD_REFs in SRA
@ 2023-10-12 10:44 Richard Biener
  0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2023-10-12 10:44 UTC (permalink / raw)
  To: gcc-patches; +Cc: Martin Jambor, fortran

The following handles byte-aligned, power-of-two and byte-multiple
sized BIT_FIELD_REF reads in SRA.  In particular this should cover
BIT_FIELD_REFs created by optimize_bit_field_compare.

For gcc.dg/tree-ssa/ssa-dse-26.c we now SRA the BIT_FIELD_REF
appearing there leading to more DSE, fully eliding the aggregates.

This results in the same false positive -Wuninitialized as the
older attempt to remove the folding from optimize_bit_field_compare,
fixed by initializing part of the aggregate unconditionally.

Bootstrapped and tested on x86_64-unknown-linux-gnu for all languages.

Martin is on leave so I'll push this tomorrow unless the Fortran
folks have objections.

Thanks,
Richard.

	PR tree-optimization/111779
gcc/
	* tree-sra.cc (sra_handled_bf_read_p): New function.
	(build_access_from_expr_1): Handle some BIT_FIELD_REFs.
	(sra_modify_expr): Likewise.
	(make_fancy_name_1): Skip over BIT_FIELD_REF.

gcc/fortran/
	* trans-expr.cc (gfc_trans_assignment_1): Initialize
	lhs_caf_attr and rhs_caf_attr codimension flag to avoid
	false positive -Wuninitialized.

gcc/testsuite/
	* gcc.dg/tree-ssa/ssa-dse-26.c: Adjust for more DSE.
	* gcc.dg/vect/vect-pr111779.c: New testcase.
---
 gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c |  4 +-
 gcc/testsuite/gcc.dg/vect/vect-pr111779.c  | 56 ++++++++++++++++++++++
 gcc/tree-sra.cc                            | 24 ++++++++--
 3 files changed, 79 insertions(+), 5 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/vect/vect-pr111779.c

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c
index e3c33f49ef6..43152de5616 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dse-26.c
@@ -31,5 +31,5 @@ constraint_equal (struct constraint a, struct constraint b)
     && constraint_expr_equal (a.rhs, b.rhs);
 }
 
-/* { dg-final { scan-tree-dump-times "Deleted dead store: x = " 1 "dse1" } } */
-/* { dg-final { scan-tree-dump-times "Deleted dead store: y = " 1 "dse1" } } */
+/* { dg-final { scan-tree-dump-times "Deleted dead store: x = " 2 "dse1" } } */
+/* { dg-final { scan-tree-dump-times "Deleted dead store: y = " 2 "dse1" } } */
diff --git a/gcc/testsuite/gcc.dg/vect/vect-pr111779.c b/gcc/testsuite/gcc.dg/vect/vect-pr111779.c
new file mode 100644
index 00000000000..79b72aebc78
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-pr111779.c
@@ -0,0 +1,56 @@
+#include <stdbool.h>
+#include "tree-vect.h"
+
+struct C
+{
+    int c;
+    int d;
+    bool f :1;
+    float e;
+};
+
+struct A
+{
+  unsigned int a;
+  unsigned char c1, c2;
+  bool b1 : 1;
+  bool b2 : 1;
+  bool b3 : 1;
+  struct C b4;
+};
+
+void __attribute__((noipa))
+foo (const struct A * __restrict x, int y)
+{
+  int s = 0, i = 0;
+  for (i = 0; i < y; ++i)
+    {
+      const struct A a = x[i];
+      s += a.b4.f ? 1 : 0;
+    }
+  if (s != 0)
+    __builtin_abort ();
+}
+
+int
+main ()
+{
+  struct A x[100];
+  int i;
+
+  check_vect ();
+
+  __builtin_memset (x, -1, sizeof (x));
+#pragma GCC novect
+  for (i = 0; i < 100; i++)
+    {
+      x[i].b1 = false;
+      x[i].b2 = false;
+      x[i].b3 = false;
+      x[i].b4.f = false;
+    }
+  foo (x, 100);
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "LOOP VECTORIZED" "vect" { target vect_int } } } */
diff --git a/gcc/tree-sra.cc b/gcc/tree-sra.cc
index 56a8ba26135..24d0c20da6a 100644
--- a/gcc/tree-sra.cc
+++ b/gcc/tree-sra.cc
@@ -1113,6 +1113,21 @@ disqualify_base_of_expr (tree t, const char *reason)
     disqualify_candidate (t, reason);
 }
 
+/* Return true if the BIT_FIELD_REF read EXPR is handled by SRA.  */
+
+static bool
+sra_handled_bf_read_p (tree expr)
+{
+  uint64_t size, offset;
+  if (bit_field_size (expr).is_constant (&size)
+      && bit_field_offset (expr).is_constant (&offset)
+      && size % BITS_PER_UNIT == 0
+      && offset % BITS_PER_UNIT == 0
+      && pow2p_hwi (size))
+    return true;
+  return false;
+}
+
 /* Scan expression EXPR and create access structures for all accesses to
    candidates for scalarization.  Return the created access or NULL if none is
    created.  */
@@ -1123,7 +1138,8 @@ build_access_from_expr_1 (tree expr, gimple *stmt, bool write)
   struct access *ret = NULL;
   bool partial_ref;
 
-  if (TREE_CODE (expr) == BIT_FIELD_REF
+  if ((TREE_CODE (expr) == BIT_FIELD_REF
+       && (write || !sra_handled_bf_read_p (expr)))
       || TREE_CODE (expr) == IMAGPART_EXPR
       || TREE_CODE (expr) == REALPART_EXPR)
     {
@@ -1170,6 +1186,7 @@ build_access_from_expr_1 (tree expr, gimple *stmt, bool write)
     case COMPONENT_REF:
     case ARRAY_REF:
     case ARRAY_RANGE_REF:
+    case BIT_FIELD_REF:
       ret = create_access (expr, stmt, write);
       break;
 
@@ -1549,6 +1566,7 @@ make_fancy_name_1 (tree expr)
       obstack_grow (&name_obstack, buffer, strlen (buffer));
       break;
 
+    case BIT_FIELD_REF:
     case ADDR_EXPR:
       make_fancy_name_1 (TREE_OPERAND (expr, 0));
       break;
@@ -1564,7 +1582,6 @@ make_fancy_name_1 (tree expr)
 	}
       break;
 
-    case BIT_FIELD_REF:
     case REALPART_EXPR:
     case IMAGPART_EXPR:
       gcc_unreachable (); 	/* we treat these as scalars.  */
@@ -3769,7 +3786,8 @@ sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi, bool write)
   tree type, bfr, orig_expr;
   bool partial_cplx_access = false;
 
-  if (TREE_CODE (*expr) == BIT_FIELD_REF)
+  if (TREE_CODE (*expr) == BIT_FIELD_REF
+      && (write || !sra_handled_bf_read_p (*expr)))
     {
       bfr = *expr;
       expr = &TREE_OPERAND (*expr, 0);
-- 
2.35.3

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2023-10-12 11:44 [PATCH] tree-optimization/111779 - Handle some BIT_FIELD_REFs in SRA Richard Biener
2023-10-12 12:01 ` Andre Vehreschild
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2023-10-12 10:44 Richard Biener

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