[gcc r15-5232] cfgexpand: Skip doing conflicts if there is only 1 variable

[Andrew Pinski via Gcc-cvs]

https://gcc.gnu.org/g:301dab51be5d8a3c690cd9b0cea462fb11a3ad4b

commit r15-5232-g301dab51be5d8a3c690cd9b0cea462fb11a3ad4b
Author: Andrew Pinski <quic_apin...@quicinc.com>
Date:   Tue Nov 12 22:13:35 2024 -0800

    cfgexpand: Skip doing conflicts if there is only 1 variable
    
    This is a small speed up. If there is only one know stack variable, there
    is no reason figure out the scope conflicts as there are none. So don't
    go through all the live range calculations just to see there are none.
    
    Bootstrapped and tested on x86_64-linux-gnu with no regressions.
    
    gcc/ChangeLog:
    
            * cfgexpand.cc (add_scope_conflicts): Return right away
            if there are only one stack variable.
    
    Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>

Diff:
---
 gcc/cfgexpand.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/gcc/cfgexpand.cc b/gcc/cfgexpand.cc
index f3a33ff9a07d..ed890f692e58 100644
--- a/gcc/cfgexpand.cc
+++ b/gcc/cfgexpand.cc
@@ -703,6 +703,11 @@ add_scope_conflicts_1 (basic_block bb, bitmap work, bool 
for_conflict)
 static void
 add_scope_conflicts (void)
 {
+  /* If there is only one variable, there is nothing to be done as
+     there is only possible partition.  */
+  if (stack_vars_num == 1)
+    return;
+
   basic_block bb;
   bool changed;
   bitmap work = BITMAP_ALLOC (NULL);