From: Ajit Kumar Agarwal <aagarwa1@linux.ibm.com>
Date: Wed, 8 May 2024 14:21:27 +0000 (-0500)
Subject: tree-ssa-sink: Improve code sinking pass
X-Git-Tag: basepoints/gcc-16~9226
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f4b86ab09dfe258c4780fcc7567ca8a275c96e7a;p=thirdparty%2Fgcc.git

tree-ssa-sink: Improve code sinking pass

Currently, code sinking will sink code at the use points with loop having same
nesting depth. The following patch improves code sinking by placing the sunk
code in begining of the block after the labels.

2024-05-08  Ajit Kumar Agarwal  <aagarwa1@linux.ibm.com>

gcc/ChangeLog:

	PR tree-optimization/81953
	* tree-ssa-sink.cc (statement_sink_location):Sink statements at
	the begining of the basic block after labels.

gcc/testsuite/ChangeLog:

	PR tree-optimization/81953
	* gcc.dg/tree-ssa/ssa-sink-21.c: New test.
---

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-21.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-21.c
new file mode 100644
index 00000000000..d3b79ca5803
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-21.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-sink-stats" } */
+void bar();
+int j;
+void foo(int a, int b, int c, int d, int e, int f)
+{
+  int l;
+  l = a + b + c + d +e + f;
+  if (a != 5)
+    {
+      bar();
+      j = l;
+    }
+}
+/* { dg-final { scan-tree-dump {l_12\s+=\s+_4\s+\+\s+f_11\(D\);\n\s+bar\s+\(\)} sink1 } } */
diff --git a/gcc/tree-ssa-sink.cc b/gcc/tree-ssa-sink.cc
index 880d6f70a80..2f90acb7ef4 100644
--- a/gcc/tree-ssa-sink.cc
+++ b/gcc/tree-ssa-sink.cc
@@ -439,10 +439,7 @@ statement_sink_location (gimple *stmt, basic_block frombb,
 	  if (sinkbb == frombb)
 	    return false;
 
-	  if (sinkbb == gimple_bb (use))
-	    *togsi = gsi_for_stmt (use);
-	  else
-	    *togsi = gsi_after_labels (sinkbb);
+	  *togsi = gsi_after_labels (sinkbb);
 
 	  return true;
 	}