diff mbox series

[v2,11/11] constructor: Check if it is faster to load constant from memory

Message ID 20210511233535.4448-12-hjl.tools@gmail.com
State New
Headers show
Series Allow TImode/OImode/XImode in op_by_pieces operations | expand

Commit Message

H.J. Lu May 11, 2021, 11:35 p.m. UTC 
When expanding a constant constructor, don't call expand_constructor if
it is more efficient to load the data from the memory via move by pieces.

gcc/

	PR middle-end/90773
	* expr.c (expand_expr_real_1): Don't call expand_constructor if
	it is more efficient to load the data from the memory.

gcc/testsuite/

	PR middle-end/90773
	* gcc.target/i386/pr90773-24.c: New test.
	* gcc.target/i386/pr90773-25.c: Likewise.
---
 gcc/expr.c                                 | 10 ++++++++++
 gcc/testsuite/gcc.target/i386/pr90773-24.c | 22 ++++++++++++++++++++++
 gcc/testsuite/gcc.target/i386/pr90773-25.c | 20 ++++++++++++++++++++
 3 files changed, 52 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr90773-24.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr90773-25.c
diff mbox series

Patch

diff --git a/gcc/expr.c b/gcc/expr.c
index 42ef5bdf5d5..6ad7265702e 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -10885,6 +10885,16 @@  expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
 		unsigned HOST_WIDE_INT ix;
 		tree field, value;
 
+		/* Check if it is more efficient to load the data from
+		   the memory directly.  FIXME: How many stores do we
+		   need here if not moved by pieces?  */
+		unsigned HOST_WIDE_INT bytes
+		  = tree_to_uhwi (TYPE_SIZE_UNIT (type));
+		if ((bytes / UNITS_PER_WORD) > 2
+		    && MOVE_MAX_PIECES > UNITS_PER_WORD
+		    && can_move_by_pieces (bytes, TYPE_ALIGN (type)))
+		  goto normal_inner_ref;
+
 		FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (init), ix,
 					  field, value)
 		  if (tree_int_cst_equal (field, index))
diff --git a/gcc/testsuite/gcc.target/i386/pr90773-24.c b/gcc/testsuite/gcc.target/i386/pr90773-24.c
new file mode 100644
index 00000000000..4a4b62533dc
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr90773-24.c
@@ -0,0 +1,22 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=x86-64" } */
+
+struct S
+{
+  long long s1 __attribute__ ((aligned (8)));
+  unsigned s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14;
+};
+
+const struct S array[] = {
+  { 0, 60, 640, 2112543726, 39682, 48, 16, 33, 10, 96, 2, 0, 0, 4 }
+};
+
+void
+foo (struct S *x)
+{
+  x[0] = array[0];
+}
+/* { dg-final { scan-assembler-times "movups\[\\t \]%xmm\[0-9\]+, \\(%\[\^,\]+\\)" 1 } } */
+/* { dg-final { scan-assembler-times "movups\[\\t \]%xmm\[0-9\]+, 16\\(%\[\^,\]+\\)" 1 } } */
+/* { dg-final { scan-assembler-times "movups\[\\t \]%xmm\[0-9\]+, 32\\(%\[\^,\]+\\)" 1 } } */
+/* { dg-final { scan-assembler-times "movups\[\\t \]%xmm\[0-9\]+, 48\\(%\[\^,\]+\\)" 1 } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr90773-25.c b/gcc/testsuite/gcc.target/i386/pr90773-25.c
new file mode 100644
index 00000000000..2520b670989
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr90773-25.c
@@ -0,0 +1,20 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=skylake" } */
+
+struct S
+{
+  long long s1 __attribute__ ((aligned (8)));
+  unsigned s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14;
+};
+
+const struct S array[] = {
+  { 0, 60, 640, 2112543726, 39682, 48, 16, 33, 10, 96, 2, 0, 0, 4 }
+};
+
+void
+foo (struct S *x)
+{
+  x[0] = array[0];
+}
+/* { dg-final { scan-assembler-times "vmovdqu\[\\t \]%ymm\[0-9\]+, \\(%\[\^,\]+\\)" 1 } } */
+/* { dg-final { scan-assembler-times "vmovdqu\[\\t \]%ymm\[0-9\]+, 32\\(%\[\^,\]+\\)" 1 } } */