phiopt: Fix up conditional_replacement [PR99305]

Hi!

Before my PR97690 changes, conditional_replacement would not set neg
when the nonzero arg was boolean true.
I've simplified the testing, so that it first finds the zero argument
and then checks the other argument for all the handled cases
(1, -1 and 1 << X, where the last case is what the patch added support for).
But, unfortunately I've placed the integer_all_onesp test first.
For unsigned precision 1 types such as bool integer_all_onesp, integer_onep
and integer_pow2p can all be true and the code set neg to true in that case,
which is undesirable.

The following patch tests integer_pow2p first (which is trivially true
for integer_onep too and tree_log2 in that case gives shift == 0)
and only if that isn't the case, integer_all_onesp.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2021-03-09  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/99305
	* tree-ssa-phiopt.c (conditional_replacement): Test integer_pow2p
	before integer_all_onesp instead of vice versa.

	* g++.dg/opt/pr99305.C: New test.


	Jakub

On March 9, 2021 4:40:22 PM GMT+01:00, Jakub Jelinek <jakub@redhat.com> wrote:
>Hi!
>
>Before my PR97690 changes, conditional_replacement would not set neg
>when the nonzero arg was boolean true.
>I've simplified the testing, so that it first finds the zero argument
>and then checks the other argument for all the handled cases
>(1, -1 and 1 << X, where the last case is what the patch added support
>for).
>But, unfortunately I've placed the integer_all_onesp test first.
>For unsigned precision 1 types such as bool integer_all_onesp,
>integer_onep
>and integer_pow2p can all be true and the code set neg to true in that
>case,
>which is undesirable.
>
>The following patch tests integer_pow2p first (which is trivially true
>for integer_onep too and tree_log2 in that case gives shift == 0)
>and only if that isn't the case, integer_all_onesp.
>
>Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

Ok. 

Richard. 

>2021-03-09  Jakub Jelinek  <jakub@redhat.com>
>
>	PR tree-optimization/99305
>	* tree-ssa-phiopt.c (conditional_replacement): Test integer_pow2p
>	before integer_all_onesp instead of vice versa.
>
>	* g++.dg/opt/pr99305.C: New test.
>
>--- gcc/tree-ssa-phiopt.c.jj	2021-01-22 11:41:38.078708425 +0100
>+++ gcc/tree-ssa-phiopt.c	2021-03-09 13:15:02.649094949 +0100
>@@ -808,14 +808,14 @@ conditional_replacement (basic_block con
>     nonzero_arg = arg0;
>   else
>     return false;
>-  if (integer_all_onesp (nonzero_arg))
>-    neg = true;
>-  else if (integer_pow2p (nonzero_arg))
>+  if (integer_pow2p (nonzero_arg))
>     {
>       shift = tree_log2 (nonzero_arg);
>       if (shift && POINTER_TYPE_P (TREE_TYPE (nonzero_arg)))
> 	return false;
>     }
>+  else if (integer_all_onesp (nonzero_arg))
>+    neg = true;
>   else
>     return false;
> 
>--- gcc/testsuite/g++.dg/opt/pr99305.C.jj	2021-03-09 13:39:11.040957563
>+0100
>+++ gcc/testsuite/g++.dg/opt/pr99305.C	2021-03-09 13:39:44.063589691
>+0100
>@@ -0,0 +1,26 @@
>+// PR tree-optimization/99305
>+// { dg-do compile }
>+// { dg-options "-O3 -fno-ipa-icf -fdump-tree-optimized" }
>+// { dg-final { scan-tree-dump-times " = \\\(unsigned char\\\)
>c_\[0-9]*\\\(D\\\);" 3 "optimized" } }
>+// { dg-final { scan-tree-dump-times " = \[^\n\r]* \\+ \[0-9]*;" 3
>"optimized" } }
>+// { dg-final { scan-tree-dump-times " = \[^\n\r]* <= 9;" 3
>"optimized" } }
>+// { dg-final { scan-tree-dump-not "if \\\(c_\[0-9]*\\\(D\\\) \[!=]=
>0\\\)" "optimized" } }
>+// { dg-final { scan-tree-dump-not " = PHI <" "optimized" } }
>+
>+bool
>+foo (char c)
>+{
>+  return c >= 48 && c <= 57;
>+}
>+
>+bool
>+bar (char c)
>+{
>+  return c != 0 && foo (c);
>+}
>+
>+bool
>+baz (char c)
>+{
>+  return c != 0 && c >= 48 && c <= 57;
>+}
>
>	Jakub

On 3/9/21 8:40 AM, Jakub Jelinek via Gcc-patches wrote:
> Hi!
>
> Before my PR97690 changes, conditional_replacement would not set neg
> when the nonzero arg was boolean true.
> I've simplified the testing, so that it first finds the zero argument
> and then checks the other argument for all the handled cases
> (1, -1 and 1 << X, where the last case is what the patch added support for).
> But, unfortunately I've placed the integer_all_onesp test first.
> For unsigned precision 1 types such as bool integer_all_onesp, integer_onep
> and integer_pow2p can all be true and the code set neg to true in that case,
> which is undesirable.
>
> The following patch tests integer_pow2p first (which is trivially true
> for integer_onep too and tree_log2 in that case gives shift == 0)
> and only if that isn't the case, integer_all_onesp.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2021-03-09  Jakub Jelinek  <jakub@redhat.com>
>
> 	PR tree-optimization/99305
> 	* tree-ssa-phiopt.c (conditional_replacement): Test integer_pow2p
> 	before integer_all_onesp instead of vice versa.
>
> 	* g++.dg/opt/pr99305.C: New test.
OK
jeff