diff mbox series

tree-optimization/109046 - re-combine complex loads

Message ID 20230307110906.81A03385B523@sourceware.org
State Accepted
Headers
Series tree-optimization/109046 - re-combine complex loads |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Richard Biener March 7, 2023, 11:08 a.m. UTC 
  The following addresses PR109046 by adding an optimization to forwprop
to combine a piecewise complex load to a complex load when there are
no uses of the components.  That's something useful in general and
easier to do than avoiding the splitting in complex lowering.

The testcase exercises both the manual and the complex lowering case.

Bootstrapped and tested on x86_64-unknown-linux-gnu, OK?

Thanks,
Richard.

	PR tree-optimization/109046
	* tree-ssa-forwprop.cc (pass_forwprop::execute): Combine
	piecewise complex loads.

	* gcc.dg/tree-ssa/forwprop-39.c: New testcase.
---
 gcc/testsuite/gcc.dg/tree-ssa/forwprop-39.c | 15 ++++++++++
 gcc/tree-ssa-forwprop.cc                    | 31 ++++++++++++++++++++-
 2 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/forwprop-39.c
diff mbox series

Patch

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/forwprop-39.c b/gcc/testsuite/gcc.dg/tree-ssa/forwprop-39.c
new file mode 100644
index 00000000000..eb2930e77fd
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/forwprop-39.c
@@ -0,0 +1,15 @@ 
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -O2 -fdump-tree-forwprop1 -fdump-tree-optimized" } */
+
+#include <complex.h>
+
+extern void push1(void *p, float _Complex x);
+void foo (void *q, float _Complex *x)
+{
+  float r = __real *x;
+  float i = __imag *x;
+  push1 (q, CMPLXF (r, i));
+}
+
+/* { dg-final { scan-tree-dump-not "COMPLEX_EXPR" "forwprop1" } } */
+/* { dg-final { scan-tree-dump-not "REALPART_EXPR" "optimized" } } */
diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
index 03fe0a3f6df..3111a2b96a3 100644
--- a/gcc/tree-ssa-forwprop.cc
+++ b/gcc/tree-ssa-forwprop.cc
@@ -3669,7 +3669,8 @@  pass_forwprop::execute (function *fun)
 	      /* Rewrite stores of a single-use complex build expression
 	         to component-wise stores.  */
 	      use_operand_p use_p;
-	      gimple *use_stmt;
+	      gimple *use_stmt, *def1, *def2;
+	      tree rhs2;
 	      if (single_imm_use (lhs, &use_p, &use_stmt)
 		  && gimple_store_p (use_stmt)
 		  && !gimple_has_volatile_ops (use_stmt)
@@ -3703,6 +3704,34 @@  pass_forwprop::execute (function *fun)
 		  release_defs (stmt);
 		  gsi_remove (&gsi, true);
 		}
+	      /* Rewrite a component-wise load of a complex to a complex
+		 load if the components are not used separately.  */
+	      else if (TREE_CODE (rhs) == SSA_NAME
+		       && has_single_use (rhs)
+		       && ((rhs2 = gimple_assign_rhs2 (stmt)), true)
+		       && TREE_CODE (rhs2) == SSA_NAME
+		       && has_single_use (rhs2)
+		       && (def1 = SSA_NAME_DEF_STMT (rhs),
+			   gimple_assign_load_p (def1))
+		       && (def2 = SSA_NAME_DEF_STMT (rhs2),
+			   gimple_assign_load_p (def2))
+		       && (gimple_vuse (def1) == gimple_vuse (def2))
+		       && gimple_assign_rhs_code (def1) == REALPART_EXPR
+		       && gimple_assign_rhs_code (def2) == IMAGPART_EXPR
+		       && operand_equal_p (TREE_OPERAND (gimple_assign_rhs1
+								 (def1), 0),
+					   TREE_OPERAND (gimple_assign_rhs1
+								 (def2), 0)))
+		{
+		  tree cl = TREE_OPERAND (gimple_assign_rhs1 (def1), 0);
+		  gimple_assign_set_rhs_from_tree (&gsi, unshare_expr (cl));
+		  gcc_assert (gsi_stmt (gsi) == stmt);
+		  gimple_set_vuse (stmt, gimple_vuse (def1));
+		  gimple_set_modified (stmt, true);
+		  gimple_stmt_iterator gsi2 = gsi_for_stmt (def1);
+		  gsi_remove (&gsi, false);
+		  gsi_insert_after (&gsi2, stmt, GSI_SAME_STMT);
+		}
 	      else
 		gsi_next (&gsi);
 	    }