Attachment 41899 Details for Bug 81503 – Patch under test

[patch] Patch under test

pr81503-2017-08-02b.patch (text/plain), 1.86 KB, created by Bill Schmidt on 2017-08-02 20:38:16 UTC

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Creator: Bill Schmidt

Created: 2017-08-02 20:38:16 UTC

Size: 1.86 KB

patch

obsolete

>Index: gcc/gimple-ssa-strength-reduction.c
>===================================================================
>--- gcc/gimple-ssa-strength-reduction.c	(revision 250791)
>+++ gcc/gimple-ssa-strength-reduction.c	(working copy)
>@@ -2074,6 +2074,15 @@ replace_mult_candidate (slsr_cand_t c, tree basis_
> {
>   tree target_type = TREE_TYPE (gimple_assign_lhs (c->cand_stmt));
>   enum tree_code cand_code = gimple_assign_rhs_code (c->cand_stmt);
>+  unsigned int prec = (POINTER_TYPE_P (target_type)
>+		       ? TYPE_PRECISION (sizetype)
>+		       : TYPE_PRECISION (target_type));
>+  tree maxval = (POINTER_TYPE_P (target_type)
>+		 ? TYPE_MAX_VALUE (sizetype)
>+		 : TYPE_MAX_VALUE (target_type));
>+  /*
>+  wide_int maxval = wi::max_value (prec, sgn);
>+  */
> 
>   /* It is highly unlikely, but possible, that the resulting
>      bump doesn't fit in a HWI.  Abandon the replacement
>@@ -2082,6 +2091,20 @@ replace_mult_candidate (slsr_cand_t c, tree basis_
>      types but allows for safe negation without twisted logic.  */
>   if (wi::fits_shwi_p (bump)
>       && bump.to_shwi () != HOST_WIDE_INT_MIN
>+      /* It is more likely that the bump doesn't fit in the target
>+	 type, so check whether constraining it to that type changes
>+	 the value.  For a signed type, the value mustn't change.
>+         For an unsigned type, the value may only change to a 
>+         congruent value (for negative bumps).  */
>+      && (TYPE_UNSIGNED (target_type)
>+	  || wi::eq_p (bump, wi::ext (bump, prec, SIGNED)))
>+      && (!TYPE_UNSIGNED (target_type)
>+	  || wi::eq_p (bump, wi::ext (bump, prec, UNSIGNED))
>+	  || wi::eq_p (bump + wi::to_widest (maxval) + 1,
>+		       wi::ext (bump, prec, UNSIGNED)))
>+	  /*
>+	  || wi::eq_p (bump + maxval + 1, wi::ext (bump, prec, UNSIGNED)))
>+	  */
>       /* It is not useful to replace casts, copies, negates, or adds of
> 	 an SSA name and a constant.  */
>       && cand_code != SSA_NAME

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Attachments on bug 81503: 41899