Richard Sandiford <rdsandif...@googlemail.com> wrote:
>This started out as an another attempt to find places where we had
>things like:
>
> offset_int x = wi::to_offset (...);
> x = ...x...;
>
>and change them to:
>
> offset_int x = ...wi::to_offset (...)...;
>
>with the get_ref_base_and_extent case being the main one.
>But it turned out that some of them were also multiplying or
>dividing by BITS_PER_UNIT, so it ended up also being a patch to
>convert those to shifts.
Ok and yes please.
Thanks,
Richard.
>I didn't want to cut-&-paste the 3 : log2 (BITS_PER_UNIT) conditional
>yet more times, so I added a LOG2_BITS_PER_UNIT to defaults.h. I can
>retrofit it to the existing code if that's OK at this stage.
>
>For insn-recog.ii this reduces the number of divmod_internal calls from
>7884858 to 369746.
>
>Thanks,
>Richard
>
>
>Index: gcc/ChangeLog.wide-int
>===================================================================
>--- gcc/ChangeLog.wide-int 2013-11-29 15:09:59.623293132 +0000
>+++ gcc/ChangeLog.wide-int 2013-11-29 15:11:48.611155898 +0000
>@@ -111,6 +111,7 @@
> (stabstr_U): Use wide-int interfaces.
> (dbxout_type): Update to use cst_fits_shwi_p.
> * defaults.h
>+ (LOG2_BITS_PER_UNIT): Define.
> (TARGET_SUPPORTS_WIDE_INT): Add default.
> * dfp.c: Include wide-int.h.
> (decimal_real_to_integer2): Use wide-int interfaces and rename to
>Index: gcc/alias.c
>===================================================================
>--- gcc/alias.c 2013-11-29 15:04:41.136142237 +0000
>+++ gcc/alias.c 2013-11-29 15:11:48.606155857 +0000
>@@ -2355,8 +2355,8 @@ adjust_offset_for_component_ref (tree x,
>
> offset_int woffset
> = (wi::to_offset (xoffset)
>- + wi::udiv_trunc (wi::to_offset (DECL_FIELD_BIT_OFFSET (field)),
>- BITS_PER_UNIT));
>+ + wi::lrshift (wi::to_offset (DECL_FIELD_BIT_OFFSET (field)),
>+ LOG2_BITS_PER_UNIT));
> if (!wi::fits_uhwi_p (woffset))
> {
> *known_p = false;
>Index: gcc/defaults.h
>===================================================================
>--- gcc/defaults.h 2013-11-29 15:04:41.136142237 +0000
>+++ gcc/defaults.h 2013-11-29 15:11:48.606155857 +0000
>@@ -475,6 +475,14 @@ #define DWARF_TYPE_SIGNATURE_SIZE 8
> #define BITS_PER_UNIT 8
> #endif
>
>+#if BITS_PER_UNIT == 8
>+#define LOG2_BITS_PER_UNIT 3
>+#elif BITS_PER_UNIT == 16
>+#define LOG2_BITS_PER_UNIT 4
>+#else
>+#error Unknown BITS_PER_UNIT
>+#endif
>+
> #ifndef BITS_PER_WORD
> #define BITS_PER_WORD (BITS_PER_UNIT * UNITS_PER_WORD)
> #endif
>Index: gcc/dwarf2out.c
>===================================================================
>--- gcc/dwarf2out.c 2013-11-29 15:04:41.136142237 +0000
>+++ gcc/dwarf2out.c 2013-11-29 15:40:56.188806688 +0000
>@@ -14930,7 +14930,7 @@ field_byte_offset (const_tree decl)
> object_offset_in_bits = bitpos_int;
>
> object_offset_in_bytes
>- = wi::udiv_trunc (object_offset_in_bits, BITS_PER_UNIT);
>+ = wi::lrshift (object_offset_in_bits, LOG2_BITS_PER_UNIT);
> return object_offset_in_bytes.to_shwi ();
> }
> >
>Index: gcc/gimple-fold.c
>===================================================================
>--- gcc/gimple-fold.c 2013-11-29 15:04:41.136142237 +0000
>+++ gcc/gimple-fold.c 2013-11-29 15:41:17.425983303 +0000
>@@ -2926,7 +2926,6 @@ fold_nonarray_ctor_reference (tree type,
> tree field_offset = DECL_FIELD_BIT_OFFSET (cfield);
> tree field_size = DECL_SIZE (cfield);
> offset_int bitoffset;
>- offset_int byte_offset_cst = wi::to_offset (byte_offset);
> offset_int bitoffset_end, access_end;
>
> /* Variable sized objects in static constructors makes no sense,
>@@ -2939,7 +2938,8 @@ fold_nonarray_ctor_reference (tree type,
>
> /* Compute bit offset of the field. */
> bitoffset = (wi::to_offset (field_offset)
>- + byte_offset_cst * BITS_PER_UNIT);
>+ + wi::lshift (wi::to_offset (byte_offset),
>+ LOG2_BITS_PER_UNIT));
> /* Compute bit offset where the field ends. */
> if (field_size != NULL_TREE)
> bitoffset_end = bitoffset + wi::to_offset (field_size);
>Index: gcc/gimple-ssa-strength-reduction.c
>===================================================================
>--- gcc/gimple-ssa-strength-reduction.c 2013-11-29 15:04:41.136142237
>+0000
>+++ gcc/gimple-ssa-strength-reduction.c 2013-11-29 15:40:56.188806688
>+0000
>@@ -897,7 +897,7 @@ restructure_reference (tree *pbase, tree
> c2 = 0;
> }
>
>- c4 = wi::udiv_floor (index, BITS_PER_UNIT);
>+ c4 = wi::lrshift (index, LOG2_BITS_PER_UNIT);
> c5 = backtrace_base_for_ref (&t2);
>
> *pbase = t1;
>Index: gcc/tree-dfa.c
>===================================================================
>--- gcc/tree-dfa.c 2013-11-29 15:04:41.136142237 +0000
>+++ gcc/tree-dfa.c 2013-11-29 15:41:39.513166464 +0000
>@@ -437,10 +437,8 @@ get_ref_base_and_extent (tree exp, HOST_
>
> if (this_offset && TREE_CODE (this_offset) == INTEGER_CST)
> {
>- offset_int woffset = wi::to_offset (this_offset);
>- woffset = wi::lshift (woffset,
>- (BITS_PER_UNIT == 8
>- ? 3 : exact_log2 (BITS_PER_UNIT)));
>+ offset_int woffset = wi::lshift (wi::to_offset (this_offset),
>+ LOG2_BITS_PER_UNIT);
> woffset += wi::to_offset (DECL_FIELD_BIT_OFFSET (field));
> bit_offset += woffset;
>
>@@ -505,9 +503,7 @@ get_ref_base_and_extent (tree exp, HOST_
> = wi::sext (wi::to_offset (index) - wi::to_offset (low_bound),
> TYPE_PRECISION (TREE_TYPE (index)));
> woffset *= wi::to_offset (unit_size);
>- woffset = wi::lshift (woffset,
>- (BITS_PER_UNIT == 8
>- ? 3 : exact_log2 (BITS_PER_UNIT)));
>+ woffset = wi::lshift (woffset, LOG2_BITS_PER_UNIT);
> bit_offset += woffset;
>
> /* An array ref with a constant index up in the structure
>Index: gcc/tree-ssa-alias.c
>===================================================================
>--- gcc/tree-ssa-alias.c 2013-11-29 15:04:41.136142237 +0000
>+++ gcc/tree-ssa-alias.c 2013-11-29 15:11:48.605155849 +0000
>@@ -2127,18 +2127,19 @@ stmt_kills_ref_p_1 (gimple stmt, ao_ref
> if (TREE_CODE (rbase) != MEM_REF)
> return false;
> // Compare pointers.
>- offset += mem_ref_offset (base) * BITS_PER_UNIT;
>- roffset += mem_ref_offset (rbase) * BITS_PER_UNIT;
>+ offset += wi::lshift (mem_ref_offset (base),
>+ LOG2_BITS_PER_UNIT);
>+ roffset += wi::lshift (mem_ref_offset (rbase),
>+ LOG2_BITS_PER_UNIT);
> base = TREE_OPERAND (base, 0);
> rbase = TREE_OPERAND (rbase, 0);
> }
>- if (base == rbase)
>- {
>- offset_int size = wi::to_offset (len) * BITS_PER_UNIT;
>- if (wi::les_p (offset, roffset)
>- && wi::les_p (roffset + ref->max_size, offset + size))
>- return true;
>- }
>+ if (base == rbase
>+ && wi::les_p (offset, roffset)
>+ && wi::les_p (roffset + ref->max_size,
>+ offset + wi::lshift (wi::to_offset (len),
>+ LOG2_BITS_PER_UNIT)))
>+ return true;
> break;
> }
>
