diff mbox series

[055/nnn] poly_int: find_bswap_or_nop_load

Message ID 87a80hlqww.fsf@linaro.org
State New
Headers show
Series [055/nnn] poly_int: find_bswap_or_nop_load | expand

Commit Message

Richard Sandiford Oct. 23, 2017, 5:23 p.m. UTC 
This patch handles polynomial offsets in find_bswap_or_nop_load,
which could be useful for constant-sized data at a variable offset.
It is needed for a later patch to compile.


2017-10-23  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* tree-ssa-math-opts.c (find_bswap_or_nop_load): Track polynomial
	offsets for MEM_REFs.

Comments

Jeff Law Nov. 28, 2017, 4:50 p.m. UTC | #1 
On 10/23/2017 11:23 AM, Richard Sandiford wrote:
> This patch handles polynomial offsets in find_bswap_or_nop_load,

> which could be useful for constant-sized data at a variable offset.

> It is needed for a later patch to compile.

> 

> 

> 2017-10-23  Richard Sandiford  <richard.sandiford@linaro.org>

> 	    Alan Hayward  <alan.hayward@arm.com>

> 	    David Sherwood  <david.sherwood@arm.com>

> 

> gcc/

> 	* tree-ssa-math-opts.c (find_bswap_or_nop_load): Track polynomial

> 	offsets for MEM_REFs.

OK.
jeff
diff mbox series

Patch

Index: gcc/tree-ssa-math-opts.c
===================================================================
--- gcc/tree-ssa-math-opts.c	2017-10-23 17:18:47.667056920 +0100
+++ gcc/tree-ssa-math-opts.c	2017-10-23 17:22:16.929564362 +0100
@@ -2122,35 +2122,31 @@  find_bswap_or_nop_load (gimple *stmt, tr
 
   if (TREE_CODE (base_addr) == MEM_REF)
     {
-      offset_int bit_offset = 0;
+      poly_offset_int bit_offset = 0;
       tree off = TREE_OPERAND (base_addr, 1);
 
       if (!integer_zerop (off))
 	{
-	  offset_int boff, coff = mem_ref_offset (base_addr);
-	  boff = coff << LOG2_BITS_PER_UNIT;
+	  poly_offset_int boff = mem_ref_offset (base_addr);
+	  boff <<= LOG2_BITS_PER_UNIT;
 	  bit_offset += boff;
 	}
 
       base_addr = TREE_OPERAND (base_addr, 0);
 
       /* Avoid returning a negative bitpos as this may wreak havoc later.  */
-      if (wi::neg_p (bit_offset))
+      if (may_lt (bit_offset, 0))
 	{
-	  offset_int mask = wi::mask <offset_int> (LOG2_BITS_PER_UNIT, false);
-	  offset_int tem = wi::bit_and_not (bit_offset, mask);
-	  /* TEM is the bitpos rounded to BITS_PER_UNIT towards -Inf.
-	     Subtract it to BIT_OFFSET and add it (scaled) to OFFSET.  */
-	  bit_offset -= tem;
-	  tem >>= LOG2_BITS_PER_UNIT;
+	  tree byte_offset = wide_int_to_tree
+	    (sizetype, bits_to_bytes_round_down (bit_offset));
+	  bit_offset = num_trailing_bits (bit_offset);
 	  if (offset)
-	    offset = size_binop (PLUS_EXPR, offset,
-				    wide_int_to_tree (sizetype, tem));
+	    offset = size_binop (PLUS_EXPR, offset, byte_offset);
 	  else
-	    offset = wide_int_to_tree (sizetype, tem);
+	    offset = byte_offset;
 	}
 
-      bitpos += bit_offset.to_shwi ();
+      bitpos += bit_offset.force_shwi ();
     }
 
   if (!multiple_p (bitpos, BITS_PER_UNIT, &bytepos))