[ARM] Fix PR target/63209

The attached patch fixed the problem reported in PR63209. The problem
exists in both gcc4.9 and trunk.

Regression test on arm-unknown-linux-gnueabi passes.

Ok for gcc-4.9 and trunk?

(I sent the patch last night, but it got lost somehow)


David

On 09/09/14 16:58, Xinliang David Li wrote:
> The attached patch fixed the problem reported in PR63209. The problem
> exists in both gcc4.9 and trunk.
> 
> Regression test on arm-unknown-linux-gnueabi passes.
> 
> Ok for gcc-4.9 and trunk?
> 

No, this isn't right.  I don't think you need a new pattern here (you
certainly don't want a new insn - at most you would just need a new
split).  But I think you just need some special case code in the
existing pattern to handle the overlap case.

Also, please do not post ChangeLog entries in patch format; they won't
apply by the time the patch is ready to be committed.

R.


> (I sent the patch last night, but it got lost somehow)
> 
> 
> David
> 
> 
> pr63209.txt
> 
> 
> Index: ChangeLog
> ===================================================================
> --- ChangeLog	(revision 215039)
> +++ ChangeLog	(working copy)
> @@ -1,3 +1,9 @@
> +2014-09-08  Xinliang David Li  <davidxl@google.com>
> +
> +	PR target/63209
> +	* config/arm/arm.md (movcond_addsi_1): New pattern.
> +	(movcond_addsi): Add a constraint.
> +
>  2014-09-08  Trevor Saunders  <tsaunders@mozilla.com>
>  
>  	* common/config/picochip/picochip-common.c: Remove.
> Index: config/arm/arm.md
> ===================================================================
> --- config/arm/arm.md	(revision 215039)
> +++ config/arm/arm.md	(working copy)
> @@ -9302,6 +9302,43 @@
>     (set_attr "type" "multiple")]
>  )
>  
> +(define_insn_and_split "movcond_addsi_1"
> +   [(set (match_operand:SI 0 "s_register_operand" "=r,l,r")
> +        (if_then_else:SI
> +         (match_operator 4 "comparison_operator"
> +          [(plus:SI (match_operand:SI 2 "s_register_operand" "r,r,r")
> +                    (match_operand:SI 3 "arm_add_operand" "rIL,rIL,rIL"))
> +             (const_int 0)])
> +         (match_operand:SI 1 "arm_rhs_operand" "rI,rPy,r")
> +         (match_dup:SI 0)))
> +    (clobber (reg:CC CC_REGNUM))]
> +    "TARGET_32BIT"
> +    "#"
> +    "&& reload_completed"
> +   [(set (reg:CC_NOOV CC_REGNUM)
> +        (compare:CC_NOOV
> +         (plus:SI (match_dup 2)
> +                  (match_dup 3))
> +         (const_int 0)))
> +    (cond_exec (match_dup 5)
> +              (set (match_dup 0) (match_dup 1)))]
> +   "
> +   {
> +     enum machine_mode mode = SELECT_CC_MODE (GET_CODE (operands[4]),
> +                                             operands[2], operands[3]);
> +     enum rtx_code rc = GET_CODE (operands[4]);
> +
> +     operands[5] = gen_rtx_REG (mode, CC_REGNUM);
> +     gcc_assert (!(mode == CCFPmode || mode == CCFPEmode));
> +     operands[5] = gen_rtx_fmt_ee (rc, VOIDmode, operands[5], const0_rtx);
> +  }
> +  "
> +  [(set_attr "conds" "clob")
> +   (set_attr "enabled_for_depr_it" "no,yes,yes")
> +   (set_attr "type" "multiple")]
> +)
> +
> +
>  (define_insn_and_split "movcond_addsi"
>    [(set (match_operand:SI 0 "s_register_operand" "=r,l,r")
>  	(if_then_else:SI
> @@ -9312,7 +9349,7 @@
>  	 (match_operand:SI 1 "arm_rhs_operand" "rI,rPy,r")
>  	 (match_operand:SI 2 "arm_rhs_operand" "rI,rPy,r")))
>     (clobber (reg:CC CC_REGNUM))]
> -   "TARGET_32BIT"
> +   "TARGET_32BIT && REGNO (operands[2]) != REGNO (operands[0])"
>     "#"
>     "&& reload_completed"
>    [(set (reg:CC_NOOV CC_REGNUM)
> Index: testsuite/ChangeLog
> ===================================================================
> --- testsuite/ChangeLog	(revision 215039)
> +++ testsuite/ChangeLog	(working copy)
> @@ -1,3 +1,8 @@
> +2014-09-08  Xinliang David Li  <davidxl@google.com>
> +
> +	PR target/63209
> +	* gcc.c-torture/execute/pr63209.c: New test
> +
>  2014-09-08  Jakub Jelinek  <jakub@redhat.com>
>  
>  	PR tree-optimization/60196
> Index: testsuite/gcc.c-torture/execute/pr63209.c
> ===================================================================
> --- testsuite/gcc.c-torture/execute/pr63209.c	(revision 0)
> +++ testsuite/gcc.c-torture/execute/pr63209.c	(revision 0)
> @@ -0,0 +1,27 @@
> +static int Sub(int a, int b) {
> +  return  b -a;
> +}
> +
> +static unsigned Select(unsigned a, unsigned b, unsigned c) {
> +  const int pa_minus_pb =
> +      Sub((a >>  8) & 0xff, (b >>  8) & 0xff) + 
> +      Sub((a >>  0) & 0xff, (b >>  0) & 0xff); 
> +  return (pa_minus_pb <= 0) ? a : b;
> +}
> +
> +__attribute__((noinline)) unsigned Predictor(unsigned left, const unsigned* const top) {
> +  const unsigned pred = Select(top[1], left, top[0]);
> +  return pred;
> +}
> +
> +int main(void) {
> +  const unsigned top[2] = {0xff7a7a7a, 0xff7a7a7a};
> +  const unsigned left = 0xff7b7b7b;
> +  const unsigned pred = Predictor(left, top /*+ 1*/);
> +  if (pred == left)
> +    return 0;
> +  return 1;
> +}
> +
> +
> +
>