invoke.texi (avoid-indexed-addresses): Document new option.

	* doc/invoke.texi (avoid-indexed-addresses): Document new option.
	* config/rs6000/rs6000-protos.h (avoiding_indexed_address_p): Declare.
	* config/rs6000/rs6000.opt (avoid-indexed-addresses): New option.
	* config/rs6000/rs6000.c (rs6000_override_options): Default
	avoid-indexed-addresses on for Power6, off for everything else.
	(avoiding_indexed_address_p): New function.
	(rs6000_legitimize_address): Use it.
	(rs6000_legitimate_address): Likewise.
	* config/rs6000/rs6000.md (movXX_updateX): Likewise
	* gcc.target/powerpc/avoid-indexed-addresses.c: New test.

From-SVN: r143742

8 files changed, 122 insertions, 19 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index da53b53..5f99aab 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2009-01-28  Pat Haugen  <pthaugen@us.ibm.com>
+
+	* doc/invoke.texi (avoid-indexed-addresses): Document new option.
+	* config/rs6000/rs6000-protos.h (avoiding_indexed_address_p): Declare.
+	* config/rs6000/rs6000.opt (avoid-indexed-addresses): New option.
+	* config/rs6000/rs6000.c (rs6000_override_options): Default
+	avoid-indexed-addresses on for Power6, off for everything else.
+	(avoiding_indexed_address_p): New function.
+	(rs6000_legitimize_address): Use it.
+	(rs6000_legitimate_address): Likewise.
+	* config/rs6000/rs6000.md (movXX_updateX): Likewise
+
 2009-01-28  Kazu Hirata  <kazu@codesourcery.com>
 
 	PR tree-optimization/38997
diff --git a/gcc/config/rs6000/rs6000-protos.h b/gcc/config/rs6000/rs6000-protos.h
index 2f1b04c..4e2ecd3 100644
--- a/gcc/config/rs6000/rs6000-protos.h
+++ b/gcc/config/rs6000/rs6000-protos.h
@@ -42,6 +42,7 @@ extern void validate_condition_mode (enum rtx_code, enum machine_mode);
 extern bool legitimate_constant_pool_address_p (rtx);
 extern bool legitimate_indirect_address_p (rtx, int);
 extern bool legitimate_indexed_address_p (rtx, int);
+extern bool avoiding_indexed_address_p (enum machine_mode);
 
 extern rtx rs6000_got_register (rtx);
 extern rtx find_addr_reg (rtx);
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 6d7327b..d2ebf62 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -1987,6 +1987,13 @@ rs6000_override_options (const char *default_cpu)
       rs6000_single_float = rs6000_double_float = 1;
   }
 
+  /* If not explicitly specified via option, decide whether to generate indexed
+     load/store instructions.  */
+  if (TARGET_AVOID_XFORM == -1)
+    /* Avoid indexed addressing when targeting Power6 in order to avoid
+     the DERAT mispredict penalty.  */
+    TARGET_AVOID_XFORM = (rs6000_cpu == PROCESSOR_POWER6 && TARGET_CMPB);
+
   rs6000_init_hard_regno_mode_ok ();
 }
 
@@ -3704,6 +3711,14 @@ legitimate_indexed_address_p (rtx x, int strict)
 		  && INT_REG_OK_FOR_INDEX_P (op0, strict))));
 }
 
+bool
+avoiding_indexed_address_p (enum machine_mode mode)
+{
+  /* Avoid indexed addressing for modes that have non-indexed
+     load/store instruction forms.  */
+  return TARGET_AVOID_XFORM && !ALTIVEC_VECTOR_MODE (mode);
+}
+
 inline bool
 legitimate_indirect_address_p (rtx x, int strict)
 {
@@ -3830,6 +3845,7 @@ rs6000_legitimize_address (rtx x, rtx oldx ATTRIBUTE_UNUSED,
 	       || ((mode != DImode && mode != DFmode && mode != DDmode)
 		   || (TARGET_E500_DOUBLE && mode != DDmode)))
 	   && (TARGET_POWERPC64 || mode != DImode)
+	   && !avoiding_indexed_address_p (mode)
 	   && mode != TImode
 	   && mode != TFmode
 	   && mode != TDmode)
@@ -4441,6 +4457,7 @@ rs6000_legitimate_address (enum machine_mode mode, rtx x, int reg_ok_strict)
 	  || (mode != DFmode && mode != DDmode)
 	  || (TARGET_E500_DOUBLE && mode != DDmode))
       && (TARGET_POWERPC64 || mode != DImode)
+      && !avoiding_indexed_address_p (mode)
       && legitimate_indexed_address_p (x, reg_ok_strict))
     return 1;
   if (GET_CODE (x) == PRE_MODIFY
@@ -4459,7 +4476,8 @@ rs6000_legitimate_address (enum machine_mode mode, rtx x, int reg_ok_strict)
       && TARGET_UPDATE
       && legitimate_indirect_address_p (XEXP (x, 0), reg_ok_strict)
       && (rs6000_legitimate_offset_address_p (mode, XEXP (x, 1), reg_ok_strict)
-	  || legitimate_indexed_address_p (XEXP (x, 1), reg_ok_strict))
+	  || (!avoiding_indexed_address_p (mode)
+	      && legitimate_indexed_address_p (XEXP (x, 1), reg_ok_strict)))
       && rtx_equal_p (XEXP (XEXP (x, 1), 0), XEXP (x, 0)))
     return 1;
   if (legitimate_lo_sum_address_p (mode, x, reg_ok_strict))
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index a5a6ec1..b6f4181 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -10055,7 +10055,9 @@
 			 (match_operand:DI 2 "reg_or_aligned_short_operand" "r,I"))))
    (set (match_operand:DI 0 "gpc_reg_operand" "=b,b")
 	(plus:DI (match_dup 1) (match_dup 2)))]
-  "TARGET_POWERPC64 && TARGET_UPDATE"
+  "TARGET_POWERPC64 && TARGET_UPDATE
+   && (!avoiding_indexed_address_p (DImode)
+       || !gpc_reg_operand (operands[2], DImode))"
   "@
    ldux %3,%0,%2
    ldu %3,%2(%0)"
@@ -10067,7 +10069,11 @@
 	(match_operand:DI 3 "gpc_reg_operand" "r,r"))
    (set (match_operand:P 0 "gpc_reg_operand" "=b,b")
 	(plus:P (match_dup 1) (match_dup 2)))]
-  "TARGET_POWERPC64 && TARGET_UPDATE"
+  "TARGET_POWERPC64 && TARGET_UPDATE
+   && (!avoiding_indexed_address_p (Pmode)
+       || !gpc_reg_operand (operands[2], Pmode)
+       || (REG_P (operands[0])
+	   && REGNO (operands[0]) == STACK_POINTER_REGNUM))"
   "@
    stdux %3,%0,%2
    stdu %3,%2(%0)"
@@ -10079,7 +10085,9 @@
 			 (match_operand:SI 2 "reg_or_short_operand" "r,I"))))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_UPDATE"
+  "TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    {lux|lwzux} %3,%0,%2
    {lu|lwzu} %3,%2(%0)"
@@ -10092,7 +10100,8 @@
 			  (match_operand:DI 2 "gpc_reg_operand" "r")))))
    (set (match_operand:DI 0 "gpc_reg_operand" "=b")
 	(plus:DI (match_dup 1) (match_dup 2)))]
-  "TARGET_POWERPC64 && rs6000_gen_cell_microcode"
+  "TARGET_POWERPC64 && rs6000_gen_cell_microcode
+   && !avoiding_indexed_address_p (DImode)"
   "lwaux %3,%0,%2"
   [(set_attr "type" "load_ext_ux")])
 
@@ -10102,7 +10111,11 @@
 	(match_operand:SI 3 "gpc_reg_operand" "r,r"))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_UPDATE"
+  "TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode)
+       || (REG_P (operands[0])
+	   && REGNO (operands[0]) == STACK_POINTER_REGNUM))"
   "@
    {stux|stwux} %3,%0,%2
    {stu|stwu} %3,%2(%0)"
@@ -10114,7 +10127,9 @@
 			 (match_operand:SI 2 "reg_or_short_operand" "r,I"))))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_UPDATE"
+  "TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    lhzux %3,%0,%2
    lhzu %3,%2(%0)"
@@ -10127,7 +10142,9 @@
 			  (match_operand:SI 2 "reg_or_short_operand" "r,I")))))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_UPDATE"
+  "TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    lhzux %3,%0,%2
    lhzu %3,%2(%0)"
@@ -10140,7 +10157,9 @@
 			  (match_operand:SI 2 "reg_or_short_operand" "r,I")))))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_UPDATE && rs6000_gen_cell_microcode"
+  "TARGET_UPDATE && rs6000_gen_cell_microcode
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    lhaux %3,%0,%2
    lhau %3,%2(%0)"
@@ -10152,7 +10171,9 @@
 	(match_operand:HI 3 "gpc_reg_operand" "r,r"))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_UPDATE"
+  "TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    sthux %3,%0,%2
    sthu %3,%2(%0)"
@@ -10164,7 +10185,9 @@
 			 (match_operand:SI 2 "reg_or_short_operand" "r,I"))))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_UPDATE"
+  "TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    lbzux %3,%0,%2
    lbzu %3,%2(%0)"
@@ -10177,7 +10200,9 @@
 			  (match_operand:SI 2 "reg_or_short_operand" "r,I")))))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_UPDATE"
+  "TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    lbzux %3,%0,%2
    lbzu %3,%2(%0)"
@@ -10189,7 +10214,9 @@
 	(match_operand:QI 3 "gpc_reg_operand" "r,r"))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_UPDATE"
+  "TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    stbux %3,%0,%2
    stbu %3,%2(%0)"
@@ -10201,7 +10228,9 @@
 			 (match_operand:SI 2 "reg_or_short_operand" "r,I"))))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_HARD_FLOAT && TARGET_FPRS && TARGET_SINGLE_FLOAT && TARGET_UPDATE"
+  "TARGET_HARD_FLOAT && TARGET_FPRS && TARGET_SINGLE_FLOAT && TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    lfsux %3,%0,%2
    lfsu %3,%2(%0)"
@@ -10213,7 +10242,9 @@
 	(match_operand:SF 3 "gpc_reg_operand" "f,f"))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_HARD_FLOAT && TARGET_FPRS && TARGET_SINGLE_FLOAT && TARGET_UPDATE"
+  "TARGET_HARD_FLOAT && TARGET_FPRS && TARGET_SINGLE_FLOAT && TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    stfsux %3,%0,%2
    stfsu %3,%2(%0)"
@@ -10225,7 +10256,9 @@
 			 (match_operand:SI 2 "reg_or_short_operand" "r,I"))))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "(TARGET_SOFT_FLOAT || !TARGET_FPRS) && TARGET_UPDATE"
+  "(TARGET_SOFT_FLOAT || !TARGET_FPRS) && TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    {lux|lwzux} %3,%0,%2
    {lu|lwzu} %3,%2(%0)"
@@ -10237,7 +10270,9 @@
 	(match_operand:SF 3 "gpc_reg_operand" "r,r"))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "(TARGET_SOFT_FLOAT || !TARGET_FPRS) && TARGET_UPDATE"
+  "(TARGET_SOFT_FLOAT || !TARGET_FPRS) && TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    {stux|stwux} %3,%0,%2
    {stu|stwu} %3,%2(%0)"
@@ -10249,7 +10284,9 @@
 			 (match_operand:SI 2 "reg_or_short_operand" "r,I"))))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_HARD_FLOAT && TARGET_FPRS && TARGET_DOUBLE_FLOAT && TARGET_UPDATE"
+  "TARGET_HARD_FLOAT && TARGET_FPRS && TARGET_DOUBLE_FLOAT && TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    lfdux %3,%0,%2
    lfdu %3,%2(%0)"
@@ -10261,7 +10298,9 @@
 	(match_operand:DF 3 "gpc_reg_operand" "f,f"))
    (set (match_operand:SI 0 "gpc_reg_operand" "=b,b")
 	(plus:SI (match_dup 1) (match_dup 2)))]
-  "TARGET_HARD_FLOAT && TARGET_FPRS && TARGET_DOUBLE_FLOAT && TARGET_UPDATE"
+  "TARGET_HARD_FLOAT && TARGET_FPRS && TARGET_DOUBLE_FLOAT && TARGET_UPDATE
+   && (!avoiding_indexed_address_p (SImode)
+       || !gpc_reg_operand (operands[2], SImode))"
   "@
    stfdux %3,%0,%2
    stfdu %3,%2(%0)"
diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
index 8a40fc3..ec5373e 100644
--- a/gcc/config/rs6000/rs6000.opt
+++ b/gcc/config/rs6000/rs6000.opt
@@ -119,6 +119,10 @@ mupdate
 Target Report RejectNegative InverseMask(NO_UPDATE, UPDATE)
 Generate load/store with update instructions
 
+mavoid-indexed-addresses
+Target Report Var(TARGET_AVOID_XFORM) Init(-1)
+Avoid generation of indexed load/store instructions when possible
+
 mno-fused-madd
 Target Report RejectNegative Mask(NO_FUSED_MADD)
 Do not generate fused multiply/add instructions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 247782a..7e991c8 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -721,6 +721,7 @@ See RS/6000 and PowerPC Options.
 -msoft-float  -mhard-float  -mmultiple  -mno-multiple @gol
 -msingle-float -mdouble-float -msimple-fpu @gol
 -mstring  -mno-string  -mupdate  -mno-update @gol
+-mavoid-indexed-addresses  -mno-avoid-indexed-addresses @gol
 -mfused-madd  -mno-fused-madd  -mbit-align  -mno-bit-align @gol
 -mstrict-align  -mno-strict-align  -mrelocatable @gol
 -mno-relocatable  -mrelocatable-lib  -mno-relocatable-lib @gol
@@ -13814,6 +13815,16 @@ stack pointer is updated and the address of the previous frame is
 stored, which means code that walks the stack frame across interrupts or
 signals may get corrupted data.
 
+@item -mavoid-indexed-addresses
+@item -mno-avoid-indexed-addresses
+@opindex mavoid-indexed-addresses
+@opindex mno-avoid-indexed-addresses
+Generate code that tries to avoid (not avoid) the use of indexed load
+or store instructions. These instructions can incur a performance
+penalty on Power6 processors in certain situations, such as when
+stepping through large arrays that cross a 16M boundary.  This option
+is enabled by default when targetting Power6 and disabled otherwise.
+
 @item -mfused-madd
 @itemx -mno-fused-madd
 @opindex mfused-madd
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d6038a1..44e685b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2009-01-28  Pat Haugen  <pthaugen@us.ibm.com>
+
+	* gcc.target/powerpc/avoid-indexed-addresses.c: New test.
+
 2009-01-28  Kazu Hirata  <kazu@codesourcery.com>
 
 	PR tree-optimization/38997
diff --git a/gcc/testsuite/gcc.target/powerpc/avoid-indexed-addresses.c b/gcc/testsuite/gcc.target/powerpc/avoid-indexed-addresses.c
new file mode 100644
index 0000000..b1b0672
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/avoid-indexed-addresses.c
@@ -0,0 +1,14 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-options "-O2 -mavoid-indexed-addresses" } */
+
+/* { dg-final { scan-assembler-not "lbzx" } }
+
+/* Ensure that an indexed load is not generated with
+   -mavoid-indexed-addresses. */
+
+char
+do_one (char *base, unsigned long offset)
+{
+  return base[offset];
+}
+