Add __builtin_ppc_get_timebase to read the time base register on PowerPC.
This is required for applications that measure time at high frequencies
with high precision that can't afford a syscall.
[gcc]
2012-08-29 Tulio Magno Quites Machado Filho <tul...@linux.vnet.ibm.com>
* config/rs6000/rs6000-builtin.def: Add __builtin_ppc_get_timebase.
* config/rs6000/rs6000.c (rs6000_expand_noop_builtin): New
function to expand an expression that calls a builtin without
arguments.
(rs6000_expand_builtin): Add __builtin_ppc_get_timebase.
(rs6000_init_builtins): Likewise.
* config/rs6000/rs6000.md: Likewise.
[gcc/testsuite]
2012-08-29 Tulio Magno Quites Machado Filho <tul...@linux.vnet.ibm.com>
* gcc.target/powerpc/ppc-get-timebase.c: New file.
---
gcc/config/rs6000/rs6000-builtin.def | 3 ++
gcc/config/rs6000/rs6000.c | 31 +++++++++++++++++
gcc/config/rs6000/rs6000.md | 36 ++++++++++++++++++++
.../gcc.target/powerpc/ppc-get-timebase.c | 22 ++++++++++++
4 files changed, 92 insertions(+), 0 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/powerpc/ppc-get-timebase.c
diff --git a/gcc/config/rs6000/rs6000-builtin.def
b/gcc/config/rs6000/rs6000-builtin.def
index c8f8f86..75ad184 100644
--- a/gcc/config/rs6000/rs6000-builtin.def
+++ b/gcc/config/rs6000/rs6000-builtin.def
@@ -1429,6 +1429,9 @@ BU_SPECIAL_X (RS6000_BUILTIN_RSQRT, "__builtin_rsqrt",
RS6000_BTM_FRSQRTE,
BU_SPECIAL_X (RS6000_BUILTIN_RSQRTF, "__builtin_rsqrtf", RS6000_BTM_FRSQRTES,
RS6000_BTC_FP)
+BU_SPECIAL_X (RS6000_BUILTIN_GET_TB, "__builtin_ppc_get_timebase",
+ RS6000_BTM_POWERPC, RS6000_BTC_MISC)
+
/* Darwin CfString builtin. */
BU_SPECIAL_X (RS6000_BUILTIN_CFSTRING, "__builtin_cfstring", RS6000_BTM_ALWAYS,
RS6000_BTC_MISC)
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 6c58307..24e274d 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -9747,6 +9747,30 @@ rs6000_overloaded_builtin_p (enum rs6000_builtins fncode)
return (rs6000_builtin_info[(int)fncode].attr & RS6000_BTC_OVERLOADED) != 0;
}
+/* Expand an expression EXP that calls a builtin without arguments. */
+static rtx
+rs6000_expand_noop_builtin (enum insn_code icode, rtx target)
+{
+ rtx pat;
+ enum machine_mode tmode = insn_data[icode].operand[0].mode;
+
+ if (icode == CODE_FOR_nothing)
+ /* Builtin not supported on this processor. */
+ return 0;
+
+ if (target == 0
+ || GET_MODE (target) != tmode
+ || ! (*insn_data[icode].operand[0].predicate) (target, tmode))
+ target = gen_reg_rtx (tmode);
+
+ pat = GEN_FCN (icode) (target);
+ if (! pat)
+ return 0;
+ emit_insn (pat);
+
+ return target;
+}
+
static rtx
rs6000_expand_unop_builtin (enum insn_code icode, tree exp, rtx target)
@@ -11336,6 +11360,9 @@ rs6000_expand_builtin (tree exp, rtx target, rtx
subtarget ATTRIBUTE_UNUSED,
? CODE_FOR_bpermd_di
: CODE_FOR_bpermd_si), exp, target);
+ case RS6000_BUILTIN_GET_TB:
+ return rs6000_expand_noop_builtin (CODE_FOR_get_timebase, target);
+
case ALTIVEC_BUILTIN_MASK_FOR_LOAD:
case ALTIVEC_BUILTIN_MASK_FOR_STORE:
{
@@ -11620,6 +11647,10 @@ rs6000_init_builtins (void)
POWER7_BUILTIN_BPERMD, "__builtin_bpermd");
def_builtin ("__builtin_bpermd", ftype, POWER7_BUILTIN_BPERMD);
+ ftype = build_function_type_list (unsigned_intDI_type_node,
+ NULL_TREE);
+ def_builtin ("__builtin_ppc_get_timebase", ftype, RS6000_BUILTIN_GET_TB);
+
#if TARGET_XCOFF
/* AIX libm provides clog as __clog. */
if ((tdecl = builtin_decl_explicit (BUILT_IN_CLOG)) != NULL_TREE)
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index d5ffd81..09bdd80 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -136,6 +136,7 @@
UNSPECV_PROBE_STACK_RANGE ; probe range of stack addresses
UNSPECV_EH_RR ; eh_reg_restore
UNSPECV_ISYNC ; isync instruction
+ UNSPECV_GETTB ; get timebase built-in
])
@@ -14101,6 +14102,41 @@
""
"")
+(define_expand "get_timebase"
+ [(use (match_operand:DI 0 "gpc_reg_operand" ""))]
+ ""
+ "
+{
+ if (TARGET_POWERPC64)
+ emit_insn (gen_get_timebase_ppc64 (operands[0]));
+ else if (TARGET_POWERPC)
+ emit_insn (gen_get_timebase_ppc32 (operands[0]));
+ else
+ FAIL;
+ DONE;
+}")
+
+(define_insn "get_timebase_ppc32"
+ [(set (match_operand:DI 0 "gpc_reg_operand" "=r")
+ (unspec_volatile:DI [(const_int 0)] UNSPECV_GETTB))
+ (clobber (match_scratch:SI 1 "=r"))]
+ "TARGET_POWERPC && !TARGET_POWERPC64"
+{
+ return "mftbu %0\;"
+ "mftb %L0\;"
+ "mftbu %1\;"
+ "cmpw %0,%1\;"
+ "bne- $-16";
+})
+
+(define_insn "get_timebase_ppc64"
+ [(set (match_operand:DI 0 "gpc_reg_operand" "=r")
+ (unspec_volatile:DI [(const_int 0)] UNSPECV_GETTB))]
+ "TARGET_POWERPC64"
+{
+ return "mfspr %0, 268";
+})
+
(include "sync.md")
diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-get-timebase.c
b/gcc/testsuite/gcc.target/powerpc/ppc-get-timebase.c
new file mode 100644
index 0000000..2f40974
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/ppc-get-timebase.c
@@ -0,0 +1,22 @@
+/* { dg-do run { target { powerpc*-*-* } } } */
+
+/* Test if __builtin_ppc_get_timebase() is compatible with the current
+ processor and if it's changing between reads. A read failure might indicate
+ a Power ISA or binutils change. */
+
+#include <inttypes.h>
+
+int
+main(void)
+{
+ uint64_t t1, t2, t3;
+
+ t1 = __builtin_ppc_get_timebase ();
+ t2 = __builtin_ppc_get_timebase ();
+ t3 = __builtin_ppc_get_timebase ();
+
+ if (t1 != t2 && t1 != t3 && t2 != t3)
+ return 0;
+
+ return 1;
+}
--
1.7.7.6
