xtensa: Improve bswap[sd]i2 insn patterns

This patch makes bswap[sd]i2 better register allocation, and reconstructs
bswapsi2 in order to take advantage of GIMPLE manual byte-swapping
recognition.

gcc/ChangeLog:

	* config/xtensa/xtensa.md (bswapsi2): New expansion pattern.
	(bswapsi2_internal): Revise the template and condition, and add
	detection code for preceding the same insn in order to omit a
	"SSAI 8" instruction of the latter.
	(bswapdi2): Suppress built-in insn expansion with the corresponding
	library call when optimizing for size.

gcc/testsuite/ChangeLog:

	* gcc.target/xtensa/bswap.c: Remove test.
	* gcc.target/xtensa/bswap-O1.c: New.
	* gcc.target/xtensa/bswap-O2.c: Ditto.
	* gcc.target/xtensa/bswap-Os.c: Ditto.

diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index 2d146b7..6f5cbc5 100644 (file)
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -471,23 +471,68 @@
 \f
 ;; Byte swap.
 
-(define_insn "bswapsi2"
-  [(set (match_operand:SI 0 "register_operand" "=&a")
-       (bswap:SI (match_operand:SI 1 "register_operand" "r")))]
-  "!optimize_size"
-  "ssai\t8\;srli\t%0, %1, 16\;src\t%0, %0, %1\;src\t%0, %0, %0\;src\t%0, %1, %0"
-  [(set_attr "type"    "arith")
-   (set_attr "mode"    "SI")
-   (set_attr "length"  "15")])
+(define_expand "bswapsi2"
+  [(set (match_operand:SI 0 "register_operand" "")
+        (bswap:SI (match_operand:SI 1 "register_operand" "")))]
+  "!optimize_debug && optimize > 1"
+{
+  /* GIMPLE manual byte-swapping recognition is now activated.
+     For both built-in and manual bswaps, emit corresponding library call
+     if optimizing for size, or a series of dedicated machine instructions
+     if otherwise.  */
+  if (optimize_size)
+    emit_library_call_value (optab_libfunc (bswap_optab, SImode),
+                            operands[0], LCT_NORMAL, SImode,
+                            operands[1], SImode);
+  else
+    emit_insn (gen_bswapsi2_internal (operands[0], operands[1]));
+  DONE;
+})
 
-(define_insn "bswapdi2"
-  [(set (match_operand:DI 0 "register_operand" "=&a")
-       (bswap:DI (match_operand:DI 1 "register_operand" "r")))]
-  "!optimize_size"
-  "ssai\t8\;srli\t%0, %D1, 16\;src\t%0, %0, %D1\;src\t%0, %0, %0\;src\t%0, %D1, %0\;srli\t%D0, %1, 16\;src\t%D0, %D0, %1\;src\t%D0, %D0, %D0\;src\t%D0, %1, %D0"
-  [(set_attr "type"    "arith")
-   (set_attr "mode"    "DI")
-   (set_attr "length"  "27")])
+(define_insn "bswapsi2_internal"
+  [(set (match_operand:SI 0 "register_operand" "=a,&a")
+       (bswap:SI (match_operand:SI 1 "register_operand" "0,r")))
+   (clobber (match_scratch:SI 2 "=&a,X"))]
+  "!optimize_debug && optimize > 1 && !optimize_size"
+{
+  rtx_insn *prev_insn = prev_nonnote_nondebug_insn (insn);
+  const char *init = "ssai\t8\;";
+  static char result[64];
+  if (prev_insn && NONJUMP_INSN_P (prev_insn))
+    {
+      rtx x = PATTERN (prev_insn);
+      if (GET_CODE (x) == PARALLEL && XVECLEN (x, 0) == 2
+         && GET_CODE (XVECEXP (x, 0, 0)) == SET
+         && GET_CODE (XVECEXP (x, 0, 1)) == CLOBBER)
+       {
+         x = XEXP (XVECEXP (x, 0, 0), 1);
+         if (GET_CODE (x) == BSWAP && GET_MODE (x) == SImode)
+           init = "";
+       }
+    }
+  sprintf (result,
+          (which_alternative == 0)
+          ? "%s" "srli\t%%2, %%1, 16\;src\t%%2, %%2, %%1\;src\t%%2, %%2, %%2\;src\t%%0, %%1, %%2"
+          : "%s" "srli\t%%0, %%1, 16\;src\t%%0, %%0, %%1\;src\t%%0, %%0, %%0\;src\t%%0, %%1, %%0",
+          init);
+  return result;
+}
+   [(set_attr "type"   "arith,arith")
+    (set_attr "mode"   "SI")
+    (set_attr "length" "15,15")])
+
+(define_expand "bswapdi2"
+  [(set (match_operand:DI 0 "register_operand" "")
+       (bswap:DI (match_operand:DI 1 "register_operand" "")))]
+  "!optimize_debug && optimize > 1 && optimize_size"
+{
+  /* Replace with a single DImode library call.
+     Without this, two SImode library calls are emitted.  */
+  emit_library_call_value (optab_libfunc (bswap_optab, DImode),
+                          operands[0], LCT_NORMAL, DImode,
+                          operands[1], DImode);
+  DONE;
+})
 
 \f
 ;; Negation and one's complement.

diff --git a/gcc/testsuite/gcc.target/xtensa/bswap-O1.c b/gcc/testsuite/gcc.target/xtensa/bswap-O1.c
new file mode 100644 (file)
index 0000000..a0c885b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/xtensa/bswap-O1.c
@@ -0,0 +1,37 @@
+/* { dg-do compile } */
+/* { dg-options "-O1" } */
+
+unsigned int test_0(unsigned int a)
+{
+  return (a & 0x000000FF) << 24 |
+         (a & 0x0000FF00) << 8  |
+         (a & 0x00FF0000) >> 8  |
+         (a & 0xFF000000) >> 24;
+}
+
+unsigned int test_1(unsigned int a)
+{
+  union
+  {
+    unsigned int i;
+    unsigned char a[4];
+  } u, v;
+  u.i = a;
+  v.a[0] = u.a[3];
+  v.a[1] = u.a[2];
+  v.a[2] = u.a[1];
+  v.a[3] = u.a[0];
+  return v.i;
+}
+
+unsigned int test_2(unsigned int a)
+{
+  return __builtin_bswap32(a);
+}
+
+unsigned long long test_3(unsigned long long a)
+{
+  return __builtin_bswap64(a);
+}
+
+/* { dg-final { scan-assembler-times "call" 2 } } */

diff --git a/gcc/testsuite/gcc.target/xtensa/bswap-O2.c b/gcc/testsuite/gcc.target/xtensa/bswap-O2.c
new file mode 100644 (file)
index 0000000..4cf95b9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/xtensa/bswap-O2.c
@@ -0,0 +1,37 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+unsigned int test_0(unsigned int a)
+{
+  return (a & 0x000000FF) << 24 |
+         (a & 0x0000FF00) << 8  |
+         (a & 0x00FF0000) >> 8  |
+         (a & 0xFF000000) >> 24;
+}
+
+unsigned int test_1(unsigned int a)
+{
+  union
+  {
+    unsigned int i;
+    unsigned char a[4];
+  } u, v;
+  u.i = a;
+  v.a[0] = u.a[3];
+  v.a[1] = u.a[2];
+  v.a[2] = u.a[1];
+  v.a[3] = u.a[0];
+  return v.i;
+}
+
+unsigned int test_2(unsigned int a)
+{
+  return __builtin_bswap32(a);
+}
+
+unsigned long long test_3(unsigned long long a)
+{
+  return __builtin_bswap64(a);
+}
+
+/* { dg-final { scan-assembler-times "ssai" 4 } } */

diff --git a/gcc/testsuite/gcc.target/xtensa/bswap-Os.c b/gcc/testsuite/gcc.target/xtensa/bswap-Os.c
new file mode 100644 (file)
index 0000000..1e010fd
--- /dev/null
+++ b/gcc/testsuite/gcc.target/xtensa/bswap-Os.c
@@ -0,0 +1,37 @@
+/* { dg-do compile } */
+/* { dg-options "-Os" } */
+
+unsigned int test_0(unsigned int a)
+{
+  return (a & 0x000000FF) << 24 |
+         (a & 0x0000FF00) << 8  |
+         (a & 0x00FF0000) >> 8  |
+         (a & 0xFF000000) >> 24;
+}
+
+unsigned int test_1(unsigned int a)
+{
+  union
+  {
+    unsigned int i;
+    unsigned char a[4];
+  } u, v;
+  u.i = a;
+  v.a[0] = u.a[3];
+  v.a[1] = u.a[2];
+  v.a[2] = u.a[1];
+  v.a[3] = u.a[0];
+  return v.i;
+}
+
+unsigned int test_2(unsigned int a)
+{
+  return __builtin_bswap32(a);
+}
+
+unsigned long long test_3(unsigned long long a)
+{
+  return __builtin_bswap64(a);
+}
+
+/* { dg-final { scan-assembler-times "call" 4 } } */

diff --git a/gcc/testsuite/gcc.target/xtensa/bswap.c b/gcc/testsuite/gcc.target/xtensa/bswap.c
deleted file mode 100644 (file)
index 057a356..0000000
--- a/gcc/testsuite/gcc.target/xtensa/bswap.c
+++ /dev/null
@@ -1,14 +0,0 @@
-/* { dg-do compile } */
-/* { dg-options "-O1" } */
-
-unsigned long f32(unsigned long v)
-{
-  return __builtin_bswap32(v);
-}
-
-unsigned long long f64(unsigned long long v)
-{
-  return __builtin_bswap64(v);
-}
-
-/* { dg-final { scan-assembler-times "ssai" 2 } } */