diff mbox series

[v2] IBM Z: Use llihf and oilf to load large immediates into GPRs

Message ID 20201202150846.594803-1-iii@linux.ibm.com
State New
Headers show
Series [v2] IBM Z: Use llihf and oilf to load large immediates into GPRs | expand

Commit Message

Ilya Leoshkevich Dec. 2, 2020, 3:08 p.m. UTC 
Bootstrapped and regtested on s390x-redhat-linux.  Ok for master?

v1: https://gcc.gnu.org/pipermail/gcc-patches/2020-December/560822.html

v1 -> v2:
- Use SYMBOL_REF_P.
- Fix usage of gcc_assert.
- Use GEN_INT.



Currently GCC loads large immediates into GPRs from the literal pool,
which is not as efficient as loading two halves with llihf and oilf.

gcc/ChangeLog:

2020-11-30  Ilya Leoshkevich  <iii@linux.ibm.com>

	* config/s390/s390-protos.h (s390_const_int_pool_entry_p): New
	function.
	* config/s390/s390.c (s390_const_int_pool_entry_p): New
	function.
	* config/s390/s390.md: Add define_peephole2 that produces llihf
	and oilf.

gcc/testsuite/ChangeLog:

2020-11-30  Ilya Leoshkevich  <iii@linux.ibm.com>

	* gcc.target/s390/load-imm64-1.c: New test.
	* gcc.target/s390/load-imm64-2.c: New test.
---
 gcc/config/s390/s390-protos.h                |  1 +
 gcc/config/s390/s390.c                       | 31 ++++++++++++++++++++
 gcc/config/s390/s390.md                      | 23 +++++++++++++++
 gcc/testsuite/gcc.target/s390/load-imm64-1.c | 14 +++++++++
 gcc/testsuite/gcc.target/s390/load-imm64-2.c | 14 +++++++++
 5 files changed, 83 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/s390/load-imm64-1.c
 create mode 100644 gcc/testsuite/gcc.target/s390/load-imm64-2.c

Comments

Andreas Krebbel Dec. 2, 2020, 4:27 p.m. UTC | #1 
On 12/2/20 4:08 PM, Ilya Leoshkevich wrote:
> Bootstrapped and regtested on s390x-redhat-linux.  Ok for master?
> 
> v1: https://gcc.gnu.org/pipermail/gcc-patches/2020-December/560822.html
> 
> v1 -> v2:
> - Use SYMBOL_REF_P.
> - Fix usage of gcc_assert.
> - Use GEN_INT.
> 
> 
> 
> Currently GCC loads large immediates into GPRs from the literal pool,
> which is not as efficient as loading two halves with llihf and oilf.
> 
> gcc/ChangeLog:
> 
> 2020-11-30  Ilya Leoshkevich  <iii@linux.ibm.com>
> 
> 	* config/s390/s390-protos.h (s390_const_int_pool_entry_p): New
> 	function.
> 	* config/s390/s390.c (s390_const_int_pool_entry_p): New
> 	function.
> 	* config/s390/s390.md: Add define_peephole2 that produces llihf
> 	and oilf.
> 
> gcc/testsuite/ChangeLog:
> 
> 2020-11-30  Ilya Leoshkevich  <iii@linux.ibm.com>
> 
> 	* gcc.target/s390/load-imm64-1.c: New test.
> 	* gcc.target/s390/load-imm64-2.c: New test.

Ok. Thanks!

Andreas
diff mbox series

Patch

diff --git a/gcc/config/s390/s390-protos.h b/gcc/config/s390/s390-protos.h
index ad2f7f77c18..eb10c3f4bbb 100644
--- a/gcc/config/s390/s390-protos.h
+++ b/gcc/config/s390/s390-protos.h
@@ -135,6 +135,7 @@  extern void s390_split_access_reg (rtx, rtx *, rtx *);
 extern void print_operand_address (FILE *, rtx);
 extern void print_operand (FILE *, rtx, int);
 extern void s390_output_pool_entry (rtx, machine_mode, unsigned int);
+extern bool s390_const_int_pool_entry_p (rtx, HOST_WIDE_INT *);
 extern int s390_label_align (rtx_insn *);
 extern int s390_agen_dep_p (rtx_insn *, rtx_insn *);
 extern rtx_insn *s390_load_got (void);
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 02f18366aa1..fb48102559d 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -9400,6 +9400,37 @@  s390_output_pool_entry (rtx exp, machine_mode mode, unsigned int align)
     }
 }
 
+/* Return true if MEM refers to an integer constant in the literal pool.  If
+   VAL is not nullptr, then also fill it with the constant's value.  */
+
+bool
+s390_const_int_pool_entry_p (rtx mem, HOST_WIDE_INT *val)
+{
+  /* Try to match the following:
+     - (mem (unspec [(symbol_ref) (reg)] UNSPEC_LTREF)).
+     - (mem (symbol_ref)).  */
+
+  if (!MEM_P (mem))
+    return false;
+
+  rtx addr = XEXP (mem, 0);
+  rtx sym;
+  if (GET_CODE (addr) == UNSPEC && XINT (addr, 1) == UNSPEC_LTREF)
+    sym = XVECEXP (addr, 0, 0);
+  else
+    sym = addr;
+
+  if (!SYMBOL_REF_P (sym) || !CONSTANT_POOL_ADDRESS_P (sym))
+    return false;
+
+  rtx val_rtx = get_pool_constant (sym);
+  if (!CONST_INT_P (val_rtx))
+    return false;
+
+  if (val != nullptr)
+    *val = INTVAL (val_rtx);
+  return true;
+}
 
 /* Return an RTL expression representing the value of the return address
    for the frame COUNT steps up from the current frame.  FRAME is the
diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index 910415a5974..d4cfbdf6732 100644
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -2116,6 +2116,29 @@  (define_peephole2
   [(set (match_dup 0) (plus:DI (match_dup 1) (match_dup 2)))]
   "")
 
+; Split loading of 64-bit constants into GPRs into llihf + oilf -
+; counterintuitively, using oilf is faster than iilf.  oilf clobbers
+; cc, so cc must be dead.
+(define_peephole2
+  [(set (match_operand:DI 0 "register_operand" "")
+	(match_operand:DI 1 "memory_operand" ""))]
+  "TARGET_64BIT
+   && TARGET_EXTIMM
+   && GENERAL_REG_P (operands[0])
+   && s390_const_int_pool_entry_p (operands[1], nullptr)
+   && peep2_reg_dead_p (1, gen_rtx_REG (CCmode, CC_REGNUM))"
+  [(set (match_dup 0) (match_dup 2))
+   (parallel
+    [(set (match_dup 0) (ior:DI (match_dup 0) (match_dup 3)))
+     (clobber (reg:CC CC_REGNUM))])]
+{
+  HOST_WIDE_INT val;
+  bool ok = s390_const_int_pool_entry_p (operands[1], &val);
+  gcc_assert (ok);
+  operands[2] = GEN_INT (val & 0xFFFFFFFF00000000ULL);
+  operands[3] = GEN_INT (val & 0x00000000FFFFFFFFULL);
+})
+
 ;
 ; movsi instruction pattern(s).
 ;
diff --git a/gcc/testsuite/gcc.target/s390/load-imm64-1.c b/gcc/testsuite/gcc.target/s390/load-imm64-1.c
new file mode 100644
index 00000000000..03d17f59096
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/load-imm64-1.c
@@ -0,0 +1,14 @@ 
+/* Test that large 64-bit constants are loaded with llihf + oilf when lgrl is
+   not available.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=z9-109" } */
+
+unsigned long
+magic (void)
+{
+  return 0x3f08c5392f756cd;
+}
+
+/* { dg-final { scan-assembler-times {\n\tllihf\t} 1 { target lp64 } } } */
+/* { dg-final { scan-assembler-times {\n\toilf\t} 1 { target lp64 } } } */
diff --git a/gcc/testsuite/gcc.target/s390/load-imm64-2.c b/gcc/testsuite/gcc.target/s390/load-imm64-2.c
new file mode 100644
index 00000000000..ee0ff3b0a91
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/load-imm64-2.c
@@ -0,0 +1,14 @@ 
+/* Test that large 64-bit constants are loaded with llihf + oilf when lgrl is
+   available.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=z10" } */
+
+unsigned long
+magic (void)
+{
+  return 0x3f08c5392f756cd;
+}
+
+/* { dg-final { scan-assembler-times {\n\tllihf\t} 1 { target lp64 } } } */
+/* { dg-final { scan-assembler-times {\n\toilf\t} 1 { target lp64 } } } */