[PATCH]middle-end Fix trapping access in test PR101750

[Tamar Christina via Gcc-patches]

Hi All,

I believe PR101750 to be a testism. The reduced case accesses h[0] but h is
uninitialized and so the changes added in r12-2523 makes the compiler realize
this and replaces the code with a trap.

This fixes the case by just making the variable static.

regtested on aarch64-none-linux-gnu and no issues.

Ok for master?

Thanks,
Tamar

gcc/testsuite/ChangeLog:

PR tree-optimization/101750
* g++.dg/vect/pr99149.cc: Fix access of h.

--- inline copy of patch -- 
diff --git a/gcc/testsuite/g++.dg/vect/pr99149.cc 
b/gcc/testsuite/g++.dg/vect/pr99149.cc
index 
00ebe9d9cdf600ada8e66b4b854f0e18ad0b6a7d..4b885a5d432130d5eff3e96c833ec6c97de3e95d
 100755
--- a/gcc/testsuite/g++.dg/vect/pr99149.cc
+++ b/gcc/testsuite/g++.dg/vect/pr99149.cc
@@ -11,8 +11,8 @@ public:
   a operator*(a d) { return a(b * b - c * c, b * c + c * d.b); }
 };
 int f, g;
-class {
-  a *h;
+class mp {
+  static a *h;
   a *i;
 
 public:


-- 
diff --git a/gcc/testsuite/g++.dg/vect/pr99149.cc b/gcc/testsuite/g++.dg/vect/pr99149.cc
index 00ebe9d9cdf600ada8e66b4b854f0e18ad0b6a7d..4b885a5d432130d5eff3e96c833ec6c97de3e95d 100755
--- a/gcc/testsuite/g++.dg/vect/pr99149.cc
+++ b/gcc/testsuite/g++.dg/vect/pr99149.cc
@@ -11,8 +11,8 @@ public:
   a operator*(a d) { return a(b * b - c * c, b * c + c * d.b); }
 };
 int f, g;
-class {
-  a *h;
+class mp {
+  static a *h;
   a *i;
 
 public:

Re: [PATCH]middle-end Fix trapping access in test PR101750

[Richard Biener]

On Tue, 3 Aug 2021, Tamar Christina wrote:

> Hi All,
> 
> I believe PR101750 to be a testism. The reduced case accesses h[0] but h is
> uninitialized and so the changes added in r12-2523 makes the compiler realize
> this and replaces the code with a trap.
> 
> This fixes the case by just making the variable static.
> 
> regtested on aarch64-none-linux-gnu and no issues.
> 
> Ok for master?

I don't think that's a correct fix - the variable 'n' is global and thus
n.h could be initialized elsewhere, no?  As said in the PR, the issue
also appears when 'main' is renamed to 'foo'.

Richard.

> Thanks,
> Tamar
> 
> gcc/testsuite/ChangeLog:
> 
>   PR tree-optimization/101750
>   * g++.dg/vect/pr99149.cc: Fix access of h.
> 
> --- inline copy of patch -- 
> diff --git a/gcc/testsuite/g++.dg/vect/pr99149.cc 
> b/gcc/testsuite/g++.dg/vect/pr99149.cc
> index 
> 00ebe9d9cdf600ada8e66b4b854f0e18ad0b6a7d..4b885a5d432130d5eff3e96c833ec6c97de3e95d
>  100755
> --- a/gcc/testsuite/g++.dg/vect/pr99149.cc
> +++ b/gcc/testsuite/g++.dg/vect/pr99149.cc
> @@ -11,8 +11,8 @@ public:
>a operator*(a d) { return a(b * b - c * c, b * c + c * d.b); }
>  };
>  int f, g;
> -class {
> -  a *h;
> +class mp {
> +  static a *h;
>a *i;
>  
>  public:
> 
> 
> 

-- 
Richard Biener 
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)