[COMMITTED 1/2] Adjust on_entry cache to indicate if the value was set properly.

[Martin Sebor]

I just glanced at the patch out of curiosity and the first hunk
caught my eye.  There's nothing wrong with the change and I like
how you make the APIs const-correct!  Just a note that it looks
like the const in on the basic_block declaration might be missing
an underscore (it should be const_basic_block).  Otherwise it's
superfluous.  This is repeated in a bunch of places in the file
and its header.

Martin

diff --git a/gcc/gimple-range-cache.cc b/gcc/gimple-range-cache.cc
index 4347485cf98..bdecd212691 100644
--- a/gcc/gimple-range-cache.cc
+++ b/gcc/gimple-range-cache.cc
@@ -132,7 +132,7 @@ non_null_ref::process_name (tree name)
  class ssa_block_ranges
  {
  public:
-  virtual void set_bb_range (const basic_block bb, const irange &r) = 0;
+  virtual bool set_bb_range (const basic_block bb, const irange &r) = 0;
    virtual bool get_bb_range (irange &r, const basic_block bb) = 0;
    virtual bool bb_range_p (const basic_block bb) = 0;

On 6/23/21 8:27 AM, Andrew MacLeod via Gcc-patches wrote:
> The introduction of the sparse bitmap on-entry cache for large BB 
> functions also introduced the concept that the value we ask to be 
> written to the cache may not be properly represented.  It is limited to 
> 15 unique ranges for any given ssa-name, then  it reverts to varying for 
> any additional values to be safe.
> 
> This patch adds a boolean return value to the cache set routines, 
> allowing us to check if the value was properly written.
> 
> Other than that, no functional change.
> 
> Bootstrap on x86_64-pc-linux-gnu with no regressions.  pushed.
> 
> Andrew
>