diff mbox

[SPARC] Disable U constraint with LRA

Message ID 10524940.hq2ygGAiKI@polaris
State New
Headers show

Commit Message

Eric Botcazou Dec. 3, 2016, 5:30 p.m. UTC 
As diagnosed by DaveM, there is a bad interaction between the U constraint 
used by the SPARC port to represent "aligned" double-word registers in 32-bit 
mode and LRA; more precisely, LRA doesn't play as nice as reload with it 
because it's not declared with define_register_constraint.

Fixed by disabling the relevant alternatives in the few patterns using the 
constraint and replacing it with a simple r constraint.  This yields a clean C 
testsuite in 32-bit mode.  The generated code seems to be slightly better than 
with reload, except for one issue: LRA doesn't seem to take into account the 
REG_ALLOC_ORDER specified by the architecture for picking reload registers,
which means that it doesn't use leaf registers in leaf functions, which in 
turn blocks the leaf function optimization on SPARC.  We cannot switch SPARC 
to LRA until after this is fixed, I'm going to open an enhancement PR.

Tested on SPARC/Solaris, applied on the mainline.


2016-12-03  Eric Botcazou  <ebotcazou@adacore.com>
            David S. Miller  <davem@davemloft.net>

	* config/sparc/constraints.md (U): Adjust comment.
	* config/sparc/sparc.md (lra): New attribute.
	(enabled): For base instructions, if the lra attribute is set,
	return 1 if it is in keeping with TARGET_LRA.
	(*movdi_insn_sp32): Add lra attribute for alternatives mentioning U
	constraint and duplicate them with U replaced by r.
	(*movdf_insn_sp32): Likewise.
	(*mov<VM64:mode>_insn_sp32): Likewise.
	(*movtf_insn_sp32): Remove alternatives mentioning U constraint.

-- 
Eric Botcazou
diff mbox

Patch

Index: config/sparc/constraints.md
===================================================================
--- config/sparc/constraints.md	(revision 243172)
+++ config/sparc/constraints.md	(working copy)
@@ -166,10 +166,10 @@  (define_memory_constraint "T"
 ;; example, we have a non-offsetable MEM.  Reload will notice this
 ;; case and reload the address into a single hard register.
 ;;
-;; The real downfall of this awkward register constraint is that it does
-;; not evaluate to a true register class like a bonafide use of
-;; define_register_constraint would.  This currently means that we cannot
-;; use LRA on Sparc, since the constraint processing of LRA really depends
+;; The real downfall of this awkward register constraint is that it
+;; does not evaluate to a true register class like a bonafide use of
+;; define_register_constraint would.  This means that we cannot use
+;; it with LRA, since the constraint processing of LRA really depends
 ;; upon whether an extra constraint is for registers or not.  It uses
 ;; reg_class_for_constraint, and checks it against NO_REGS.
 (define_constraint "U"
Index: config/sparc/sparc.md
===================================================================
--- config/sparc/sparc.md	(revision 243172)
+++ config/sparc/sparc.md	(working copy)
@@ -254,8 +254,14 @@  (define_attr "isa" "v7,v8,v9,sparclet"
 (define_attr "cpu_feature" "none,fpu,fpunotv9,v9,vis,vis3,vis4"
   (const_string "none"))
 
+(define_attr "lra" "none,disabled,enabled"
+  (const_string "none"))
+
 (define_attr "enabled" ""
-  (cond [(eq_attr "cpu_feature" "none") (const_int 1)
+  (cond [(eq_attr "cpu_feature" "none")
+	   (cond [(eq_attr "lra" "disabled") (symbol_ref "!TARGET_LRA")
+		  (eq_attr "lra" "enabled") (symbol_ref "TARGET_LRA")]
+		 (const_int 1))
          (eq_attr "cpu_feature" "fpu") (symbol_ref "TARGET_FPU")
          (eq_attr "cpu_feature" "fpunotv9") (symbol_ref "TARGET_FPU && !TARGET_V9")
          (eq_attr "cpu_feature" "v9") (symbol_ref "TARGET_V9")
@@ -1701,9 +1707,9 @@  (define_expand "movdi"
 
 (define_insn "*movdi_insn_sp32"
   [(set (match_operand:DI 0 "nonimmediate_operand"
-			    "=T,o,T,U,o,r,r,r,?T,?*f,?*f,?o,?*e,?*e,  r,?*f,?*e,?W,b,b")
+			    "=T,o,T,T,U,r,o,r,r,r,?T,?*f,?*f,?o,?*e,?*e,  r,?*f,?*e,?W,b,b")
         (match_operand:DI 1 "input_operand"
-			    " J,J,U,T,r,o,i,r,*f,  T,  o,*f, *e, *e,?*f,  r,  W,*e,J,P"))]
+			    " J,J,U,r,T,T,r,o,i,r,*f,  T,  o,*f, *e, *e,?*f,  r,  W,*e,J,P"))]
   "TARGET_ARCH32
    && (register_operand (operands[0], DImode)
        || register_or_zero_operand (operands[1], DImode))"
@@ -1711,6 +1717,8 @@  (define_insn "*movdi_insn_sp32"
    stx\t%%g0, %0
    #
    std\t%1, %0
+   std\t%1, %0
+   ldd\t%1, %0
    ldd\t%1, %0
    #
    #
@@ -1728,11 +1736,12 @@  (define_insn "*movdi_insn_sp32"
    std\t%1, %0
    fzero\t%0
    fone\t%0"
-  [(set_attr "type" "store,store,store,load,*,*,*,*,fpstore,fpload,*,*,fpmove,*,*,*,fpload,fpstore,visl,visl")
-   (set_attr "length" "*,2,*,*,2,2,2,2,*,*,2,2,*,2,2,2,*,*,*,*")
-   (set_attr "fptype" "*,*,*,*,*,*,*,*,*,*,*,*,double,*,*,*,*,*,double,double")
-   (set_attr "cpu_feature" "v9,*,*,*,*,*,*,*,fpu,fpu,fpu,fpu,v9,fpunotv9,vis3,vis3,fpu,fpu,vis,vis")
-   (set_attr "v3pipe" "*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,true,true")])
+  [(set_attr "type" "store,store,store,store,load,load,*,*,*,*,fpstore,fpload,*,*,fpmove,*,*,*,fpload,fpstore,visl,visl")
+   (set_attr "length" "*,2,*,*,*,*,2,2,2,2,*,*,2,2,*,2,2,2,*,*,*,*")
+   (set_attr "fptype" "*,*,*,*,*,*,*,*,*,*,*,*,*,*,double,*,*,*,*,*,double,double")
+   (set_attr "cpu_feature" "v9,*,*,*,*,*,*,*,*,*,fpu,fpu,fpu,fpu,v9,fpunotv9,vis3,vis3,fpu,fpu,vis,vis")
+   (set_attr "v3pipe" "*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,true,true")
+   (set_attr "lra" "*,*,disabled,enabled,disabled,enabled,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*")])
 
 (define_insn "*movdi_insn_sp64"
   [(set (match_operand:DI 0 "nonimmediate_operand" "=r,r,r, m, r,*e,?*e,?*e,?W,b,b")
@@ -2372,9 +2381,9 @@  (define_expand "movdf"
 
 (define_insn "*movdf_insn_sp32"
   [(set (match_operand:DF 0 "nonimmediate_operand"
-			    "=b,b,e,e,*r, f,  e,T,W,U,T,  f,  *r,  o,o")
+			    "=b,b,e,e,*r, f,  e,T,W,U,r,T,T,  f,  *r,  o,o")
 	(match_operand:DF 1 "input_operand"
-			    " G,C,e,e, f,*r,W#F,G,e,T,U,o#F,*roF,*rG,f"))]
+			    " G,C,e,e, f,*r,W#F,G,e,T,T,U,r,o#F,*roF,*rG,f"))]
   "TARGET_ARCH32
    && (register_operand (operands[0], DFmode)
        || register_or_zero_or_all_ones_operand (operands[1], DFmode))"
@@ -2389,16 +2398,19 @@  (define_insn "*movdf_insn_sp32"
   stx\t%r1, %0
   std\t%1, %0
   ldd\t%1, %0
+  ldd\t%1, %0
+  std\t%1, %0
   std\t%1, %0
   #
   #
   #
   #"
-  [(set_attr "type" "visl,visl,fpmove,*,*,*,fpload,store,fpstore,load,store,*,*,*,*")
-   (set_attr "length" "*,*,*,2,2,2,*,*,*,*,*,2,2,2,2")
-   (set_attr "fptype" "double,double,double,*,*,*,*,*,*,*,*,*,*,*,*")
-   (set_attr "cpu_feature" "vis,vis,v9,fpunotv9,vis3,vis3,fpu,v9,fpu,*,*,fpu,*,*,fpu")
-   (set_attr "v3pipe" "true,true,*,*,*,*,*,*,*,*,*,*,*,*,*")])
+  [(set_attr "type" "visl,visl,fpmove,*,*,*,fpload,store,fpstore,load,load,store,store,*,*,*,*")
+   (set_attr "length" "*,*,*,2,2,2,*,*,*,*,*,*,*,2,2,2,2")
+   (set_attr "fptype" "double,double,double,*,*,*,*,*,*,*,*,*,*,*,*,*,*")
+   (set_attr "cpu_feature" "vis,vis,v9,fpunotv9,vis3,vis3,fpu,v9,fpu,*,*,*,*,fpu,*,*,fpu")
+   (set_attr "v3pipe" "true,true,*,*,*,*,*,*,*,*,*,*,*,*,*,*,*")
+   (set_attr "lra" "*,*,*,*,*,*,*,*,*,disabled,enabled,disabled,enabled,*,*,*,*")])
 
 (define_insn "*movdf_insn_sp64"
   [(set (match_operand:DF 0 "nonimmediate_operand" "=b,b,e,*r, e,  e,W, *r,*r,  m,*r")
@@ -2609,14 +2621,14 @@  (define_expand "movtf"
 })
 
 (define_insn "*movtf_insn_sp32"
-  [(set (match_operand:TF 0 "nonimmediate_operand" "=b, e,o,  o,U,  r")
-	(match_operand:TF 1 "input_operand"        " G,oe,e,rGU,o,roG"))]
+  [(set (match_operand:TF 0 "nonimmediate_operand" "=b, e,o, o,  r")
+	(match_operand:TF 1 "input_operand"        " G,oe,e,rG,roG"))]
   "TARGET_ARCH32
    && (register_operand (operands[0], TFmode)
        || register_or_zero_operand (operands[1], TFmode))"
   "#"
-  [(set_attr "length" "4,4,4,4,4,4")
-   (set_attr "cpu_feature" "fpu,fpu,fpu,*,*,*")])
+  [(set_attr "length" "4,4,4,4,4")
+   (set_attr "cpu_feature" "fpu,fpu,fpu,*,*")])
 
 (define_insn "*movtf_insn_sp64"
   [(set (match_operand:TF 0 "nonimmediate_operand" "=b, e,o, o,  r")
@@ -8636,8 +8648,8 @@  (define_insn "*mov<VM64:mode>_insn_sp64"
    (set_attr "v3pipe" "true,true,true,*,*,*,*,*,*,*,*")])
 
 (define_insn "*mov<VM64:mode>_insn_sp32"
-  [(set (match_operand:VM64 0 "nonimmediate_operand" "=e,e,e,*r, f,e,m,m,U,T, o,*r")
-	(match_operand:VM64 1 "input_operand"         "Y,C,e, f,*r,m,e,Y,T,U,*r,*r"))]
+  [(set (match_operand:VM64 0 "nonimmediate_operand" "=e,e,e,*r, f,e,m,m,U,r,T,T, o,*r")
+	(match_operand:VM64 1 "input_operand"         "Y,C,e, f,*r,m,e,Y,T,T,U,r,*r,*r"))]
   "TARGET_VIS
    && TARGET_ARCH32
    && (register_operand (operands[0], <VM64:MODE>mode)
@@ -8652,13 +8664,16 @@  (define_insn "*mov<VM64:mode>_insn_sp32"
   std\t%1, %0
   stx\t%r1, %0
   ldd\t%1, %0
+  ldd\t%1, %0
+  std\t%1, %0
   std\t%1, %0
   #
   #"
-  [(set_attr "type" "visl,visl,vismv,*,*,fpload,fpstore,store,load,store,*,*")
-   (set_attr "length" "*,*,*,2,2,*,*,*,*,*,2,2")
-   (set_attr "cpu_feature" "vis,vis,vis,vis3,vis3,*,*,*,*,*,*,*")
-   (set_attr "v3pipe" "true,true,true,*,*,*,*,*,*,*,*,*")])
+  [(set_attr "type" "visl,visl,vismv,*,*,fpload,fpstore,store,load,load,store,store,*,*")
+   (set_attr "length" "*,*,*,2,2,*,*,*,*,*,*,*,2,2")
+   (set_attr "cpu_feature" "vis,vis,vis,vis3,vis3,*,*,*,*,*,*,*,*,*")
+   (set_attr "v3pipe" "true,true,true,*,*,*,*,*,*,*,*,*,*,*")
+   (set_attr "lra" "*,*,*,*,*,*,*,*,disabled,enabled,disabled,enabled,*,*")])
 
 (define_split
   [(set (match_operand:VM64 0 "memory_operand" "")