[PATCH] Fix pointer sharing in Value_Range constructor.

[PATCH] Fix pointer sharing in Value_Range constructor.

[Aldy Hernandez]

I will push this when a final round of testing finishes on x86-64 Linux.

gcc/ChangeLog:

	* value-range.h (Value_Range::Value_Range): Avoid pointer sharing.
---
 gcc/value-range.h | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/gcc/value-range.h b/gcc/value-range.h
index 0eeea79b322..f97596cdd14 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -583,7 +583,18 @@ Value_Range::Value_Range (tree min, tree max, value_range_kind kind)
 inline
 Value_Range::Value_Range (const Value_Range &r)
 {
-  m_vrange = r.m_vrange;
+  if (r.m_vrange == &r.m_irange)
+    {
+      m_irange = r.m_irange;
+      m_vrange = &m_irange;
+    }
+  else if (r.m_vrange == &r.m_frange)
+    {
+      m_frange = r.m_frange;
+      m_vrange = &m_frange;
+    }
+  else
+    m_vrange = &m_unsupported;
 }
 
 // Initialize object so it is possible to store temporaries of TYPE
-- 
2.39.2

Re: [PATCH] Fix pointer sharing in Value_Range constructor.

[Aldy Hernandez]

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On 4/18/23 18:40, Aldy Hernandez wrote:
> I will push this when a final round of testing finishes on x86-64 Linux.
> 
> gcc/ChangeLog:
> 
> 	* value-range.h (Value_Range::Value_Range): Avoid pointer sharing.
> ---
>   gcc/value-range.h | 13 ++++++++++++-
>   1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/gcc/value-range.h b/gcc/value-range.h
> index 0eeea79b322..f97596cdd14 100644
> --- a/gcc/value-range.h
> +++ b/gcc/value-range.h
> @@ -583,7 +583,18 @@ Value_Range::Value_Range (tree min, tree max, value_range_kind kind)
>   inline
>   Value_Range::Value_Range (const Value_Range &r)
>   {
> -  m_vrange = r.m_vrange;
> +  if (r.m_vrange == &r.m_irange)
> +    {
> +      m_irange = r.m_irange;
> +      m_vrange = &m_irange;
> +    }
> +  else if (r.m_vrange == &r.m_frange)
> +    {
> +      m_frange = r.m_frange;
> +      m_vrange = &m_frange;
> +    }
> +  else
> +    m_vrange = &m_unsupported;
>   }
>   
>   // Initialize object so it is possible to store temporaries of TYPE

Upon further thought I realized operator= will do all the right things, 
and makes the code easier to read.

Re-tested and pushed.

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From fc03caa0c94c9c11e0c1b1f7e7eba64233dbcfec Mon Sep 17 00:00:00 2001
From: Aldy Hernandez <aldyh@redhat.com>
Date: Mon, 6 Mar 2023 13:53:15 +0100
Subject: [PATCH] Fix pointer sharing in Value_Range constructor.

gcc/ChangeLog:

	* value-range.h (Value_Range::Value_Range): Avoid pointer sharing.
---
 gcc/value-range.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/value-range.h b/gcc/value-range.h
index 0eeea79b322..33ef3b5b8d8 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -583,7 +583,7 @@ Value_Range::Value_Range (tree min, tree max, value_range_kind kind)
 inline
 Value_Range::Value_Range (const Value_Range &r)
 {
-  m_vrange = r.m_vrange;
+  *this = *r.m_vrange;
 }
 
 // Initialize object so it is possible to store temporaries of TYPE
-- 
2.40.0