gcc/

	PR target/53916
	* config/mips/constraints.md (kl): New constraint.
	* config/mips/mips.md (divmod<mode>4, udivmod<mode>4): Delete.
	(divmod<mode>4_internal): Rename to divmod<mode>4.  Use "kl" as the
	constraint for operand 0.  Split after CSE for MIPS16.  Emit a move
	from LO for MIPS16.
	(udivmod<mode>4_internal): Likewise udivmod<mode>4.

gcc/testsuite/
	PR target/53916
	* gcc.target/mips/div-13.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@199329 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 58 insertions, 50 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 89936afd71d..e2879fc338f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,15 @@
 2013-05-25  Richard Sandiford  <rdsandiford@googlemail.com>
 
+	PR target/53916
+	* config/mips/constraints.md (kl): New constraint.
+	* config/mips/mips.md (divmod<mode>4, udivmod<mode>4): Delete.
+	(divmod<mode>4_internal): Rename to divmod<mode>4.  Use "kl" as the
+	constraint for operand 0.  Split after CSE for MIPS16.  Emit a move
+	from LO for MIPS16.
+	(udivmod<mode>4_internal): Likewise udivmod<mode>4.
+
+2013-05-25  Richard Sandiford  <rdsandiford@googlemail.com>
+
 	PR target/55777
 	* config/mips/mips.c (mips_can_inline_p): New function.
 	(TARGET_CAN_INLINE_P): Define.
diff --git a/gcc/config/mips/constraints.md b/gcc/config/mips/constraints.md
index ddef8cc495d..1fe6119d075 100644
--- a/gcc/config/mips/constraints.md
+++ b/gcc/config/mips/constraints.md
@@ -92,6 +92,12 @@
 ;; but the DSP version allows any accumulator target.
 (define_register_constraint "ka" "ISA_HAS_DSP_MULT ? ACC_REGS : MD_REGS")
 
+;; The register class to use for an allocatable division result.
+;; MIPS16 uses M16_REGS because LO is fixed.
+(define_register_constraint "kl"
+  "TARGET_MIPS16 ? M16_REGS : TARGET_BIG_ENDIAN ? MD1_REG : MD0_REG"
+  "@internal")
+
 (define_constraint "kf"
   "@internal"
   (match_operand 0 "force_to_mem_operand"))
diff --git a/gcc/config/mips/mips.md b/gcc/config/mips/mips.md
index 7284e5f3384..6f6484b0d8c 100644
--- a/gcc/config/mips/mips.md
+++ b/gcc/config/mips/mips.md
@@ -2560,80 +2560,50 @@
 
 ;; VR4120 errata MD(A1): signed division instructions do not work correctly
 ;; with negative operands.  We use special libgcc functions instead.
-(define_expand "divmod<mode>4"
-  [(set (match_operand:GPR 0 "register_operand")
-	(div:GPR (match_operand:GPR 1 "register_operand")
-		 (match_operand:GPR 2 "register_operand")))
-   (set (match_operand:GPR 3 "register_operand")
-	(mod:GPR (match_dup 1)
-		 (match_dup 2)))]
-  "!TARGET_FIX_VR4120"
-{
-  if (TARGET_MIPS16)
-    {
-      emit_insn (gen_divmod<mode>4_split (operands[3], operands[1],
-					  operands[2]));
-      emit_move_insn (operands[0], gen_rtx_REG (<MODE>mode, LO_REGNUM));
-    }
-  else
-    emit_insn (gen_divmod<mode>4_internal (operands[0], operands[1],
-					   operands[2], operands[3]));
-  DONE;
-})
-
-(define_insn_and_split "divmod<mode>4_internal"
-  [(set (match_operand:GPR 0 "muldiv_target_operand" "=l")
+;;
+;; Expand generates divmod instructions for individual division and modulus
+;; operations.  We then rely on CSE to reuse earlier divmods where possible.
+;; This means that, when generating MIPS16 code, it is better not to expose
+;; the fixed LO register until after CSE has finished.  However, it's still
+;; better to split before register allocation, so that we don't allocate
+;; one of the scarce MIPS16 registers to an unused result.
+(define_insn_and_split "divmod<mode>4"
+  [(set (match_operand:GPR 0 "register_operand" "=kl")
 	(div:GPR (match_operand:GPR 1 "register_operand" "d")
 		 (match_operand:GPR 2 "register_operand" "d")))
    (set (match_operand:GPR 3 "register_operand" "=d")
 	(mod:GPR (match_dup 1)
 		 (match_dup 2)))]
-  "!TARGET_FIX_VR4120 && !TARGET_MIPS16"
+  "!TARGET_FIX_VR4120"
   "#"
-  "&& reload_completed"
+  "&& ((TARGET_MIPS16 && cse_not_expected) || reload_completed)"
   [(const_int 0)]
 {
   emit_insn (gen_divmod<mode>4_split (operands[3], operands[1], operands[2]));
+  if (TARGET_MIPS16)
+    emit_move_insn (operands[0], gen_rtx_REG (<MODE>mode, LO_REGNUM));
   DONE;
 }
  [(set_attr "type" "idiv")
   (set_attr "mode" "<MODE>")
   (set_attr "length" "8")])
 
-(define_expand "udivmod<mode>4"
-  [(set (match_operand:GPR 0 "register_operand")
-	(udiv:GPR (match_operand:GPR 1 "register_operand")
-		  (match_operand:GPR 2 "register_operand")))
-   (set (match_operand:GPR 3 "register_operand")
-	(umod:GPR (match_dup 1)
-		  (match_dup 2)))]
-  ""
-{
-  if (TARGET_MIPS16)
-    {
-      emit_insn (gen_udivmod<mode>4_split (operands[3], operands[1],
-					   operands[2]));
-      emit_move_insn (operands[0], gen_rtx_REG (<MODE>mode, LO_REGNUM));
-    }
-  else
-    emit_insn (gen_udivmod<mode>4_internal (operands[0], operands[1],
-					    operands[2], operands[3]));
-  DONE;
-})
-
-(define_insn_and_split "udivmod<mode>4_internal"
-  [(set (match_operand:GPR 0 "muldiv_target_operand" "=l")
+;; See the comment above "divmod<mode>4" for the MIPS16 handling.
+(define_insn_and_split "udivmod<mode>4"
+  [(set (match_operand:GPR 0 "register_operand" "=kl")
 	(udiv:GPR (match_operand:GPR 1 "register_operand" "d")
 		  (match_operand:GPR 2 "register_operand" "d")))
    (set (match_operand:GPR 3 "register_operand" "=d")
 	(umod:GPR (match_dup 1)
 		  (match_dup 2)))]
-  "!TARGET_MIPS16"
+  ""
   "#"
-  "reload_completed"
+  "(TARGET_MIPS16 && cse_not_expected) || reload_completed"
   [(const_int 0)]
 {
   emit_insn (gen_udivmod<mode>4_split (operands[3], operands[1], operands[2]));
+  if (TARGET_MIPS16)
+    emit_move_insn (operands[0], gen_rtx_REG (<MODE>mode, LO_REGNUM));
   DONE;
 }
  [(set_attr "type" "idiv")
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index fbc87164103..38985d6119a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2013-05-25  Richard Sandiford  <rdsandiford@googlemail.com>
 
+	PR target/53916
+	* gcc.target/mips/div-13.c: New test.
+
+2013-05-25  Richard Sandiford  <rdsandiford@googlemail.com>
+
 	PR target/55777
 	* gcc.target/mips/mips16-attributes-5.c,
 	* gcc.target/mips/mips16-attributes-6.c: New tests.
diff --git a/gcc/testsuite/gcc.target/mips/div-13.c b/gcc/testsuite/gcc.target/mips/div-13.c
new file mode 100644
index 00000000000..cf746a66306
--- /dev/null
+++ b/gcc/testsuite/gcc.target/mips/div-13.c
@@ -0,0 +1,17 @@
+/* { dg-options "(-mips16) -mgp64" } */
+/* { dg-skip-if "code quality test" { *-*-* } { "-O0" } { "" } } */
+
+typedef int int32_t;
+typedef unsigned int uint32_t;
+typedef long long int64_t;
+typedef unsigned long long uint64_t;
+
+MIPS16 int32_t f1 (int32_t x, int32_t y) { return x / y + x % y; }
+MIPS16 uint32_t f2 (uint32_t x, uint32_t y) { return x / y + x % y; }
+MIPS16 int64_t f3 (int64_t x, int64_t y) { return x / y + x % y; }
+MIPS16 uint64_t f4 (uint64_t x, uint64_t y) { return x / y + x % y; }
+
+/* { dg-final { scan-assembler-times "\tdiv\t" 1 } } */
+/* { dg-final { scan-assembler-times "\tdivu\t" 1 } } */
+/* { dg-final { scan-assembler-times "\tddiv\t" 1 } } */
+/* { dg-final { scan-assembler-times "\tddivu\t" 1 } } */