alpha.h (TARGET_FIXUP_EV5_PREFETCH): New.

        * config/alpha/alpha.h (TARGET_FIXUP_EV5_PREFETCH): New.
        * config/alpha/linux.h (TARGET_FIXUP_EV5_PREFETCH): New.
        * config/alpha/alpha.md (prefetch): New.

From-SVN: r47922

gcc/ChangeLog

 2001-12-11  Richard Henderson  <rth@redhat.com>
 
+	* config/alpha/alpha.h (TARGET_FIXUP_EV5_PREFETCH): New.
+	* config/alpha/linux.h (TARGET_FIXUP_EV5_PREFETCH): New.
+	* config/alpha/alpha.md (prefetch): New.
+
+2001-12-11  Richard Henderson  <rth@redhat.com>
+
 	* combine.c (simplify_and_const_int): Simplify (AND (PLUS X Y) C)
 	if C has only low bits set and doesn't intersect with X or Y.
 

gcc/config/alpha/alpha.h

@@ -206,6 +206,9 @@ extern enum alpha_fp_trap_mode alpha_fptm;
 #ifndef TARGET_LD_BUGGY_LDGP
 #define TARGET_LD_BUGGY_LDGP 0
 #endif
+#ifndef TARGET_FIXUP_EV5_PREFETCH
+#define TARGET_FIXUP_EV5_PREFETCH 0
+#endif
 
 /* Macro to define tables used to set the flags.
    This is a list in braces of pairs in braces,

gcc/config/alpha/alpha.md

@@ -6716,6 +6716,44 @@ fadd,fmul,fcpys,fdiv,fsqrt,misc,mvi,ftoi,itof,multi"
   [(set_attr "length" "16")
    (set_attr "type" "multi")])
 
+;; Prefetch data.  
+;;
+;; On EV4, these instructions are nops -- no load occurs.
+;;
+;; On EV5, these instructions act as a normal load, and thus can trap
+;; if the address is invalid.  The OS may (or may not) handle this in
+;; the entMM fault handler and suppress the fault.  If so, then this
+;; has the effect of a read prefetch instruction.
+;;
+;; On EV6, these become official prefetch instructions.
+
+(define_insn "prefetch"
+  [(prefetch (match_operand:DI 0 "address_operand" "p")
+	     (match_operand:DI 1 "const_int_operand" "n")
+	     (match_operand:DI 2 "const_int_operand" "n"))]
+  "TARGET_FIXUP_EV5_PREFETCH || TARGET_CPU_EV6"
+{
+  /* Interpret "no temporal locality" as this data should be evicted once
+     it is used.  The "evict next" alternatives load the data into the cache
+     and leave the LRU eviction counter pointing to that block.  */
+  static const char * const alt[2][2] = {
+    { 
+      "lds $f31,%a0",		/* read, evict next */
+      "ldl $31,%a0",		/* read, evict last */
+    },
+    {
+      "ldt $f31,%a0",		/* write, evict next */
+      "ldq $31,%a0",		/* write, evict last */
+    }
+  };
+
+  bool write = INTVAL (operands[1]) != 0;
+  bool lru = INTVAL (operands[2]) != 0;
+
+  return alt[write][lru];
+}
+  [(set_attr "type" "ild")])
+
 ;; Close the trap shadow of preceding instructions.  This is generated
 ;; by alpha_reorg.
 

gcc/config/alpha/linux.h

@@ -46,6 +46,10 @@ SUB_CPP_PREDEFINES
 #undef TARGET_CAN_FAULT_IN_PROLOGUE
 #define TARGET_CAN_FAULT_IN_PROLOGUE 1
 
+/* OS fixes up EV5 data fault on prefetch.  */
+#undef TARGET_FIXUP_EV5_PREFETCH
+#define TARGET_FIXUP_EV5_PREFETCH 1
+
 #undef WCHAR_TYPE
 #define WCHAR_TYPE "int"