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From: David Holsgrove <david.holsgrove@xilinx.com>
Subject: [PATCH 8/8] [Patch, microblaze]: Add branch_compare instruction
To facilitate optimization pass understanding of the conditional
branch for microblaze, remove the UNSPEC'd signed_compare /
unsigned_compare instructions, and replace with a complete
branch_compare which will output_asm_insn the correct cmp/cmpu
depending on comparison code and signed / unsigned.
We then return the correct branch instruction.
cbranchsi now calls an expanded microblaze_expand_conditional_branch
function which will carry out compare against zero, compare EQ/NE,
and all other compares appropriately.
-funroll-loops optimization pass can now proceed
Changelog
2013-03-19 David Holsgrove <david.holsgrove@xilinx.com>
* gcc/config/microblaze/predicates.md: Add cmp_op predicate.
* gcc/config/microblaze/microblaze.md: Add branch_compare
instruction which uses cmp_op predicate and emits cmp insn
before branch.
* gcc/config/microblaze/microblaze.c
(microblaze_emit_compare): Rename to
microblaze_expand_conditional_branch and consolidate logic.
(microblaze_expand_conditional_branch): emit branch_compare
insn instead of handling cmp op separate from branch insn.
Signed-off-by: David Holsgrove <david.holsgrove@xilinx.com>
Upstream-Status: Pending
diff --git a/gcc/config/microblaze/microblaze.c b/gcc/config/microblaze/microblaze.c
index 4417289..84b58bf 100644
--- a/gcc/config/microblaze/microblaze.c
+++ b/gcc/config/microblaze/microblaze.c
@@ -3336,65 +3336,45 @@ microblaze_trampoline_init (rtx m_tramp, tree fndecl, rtx chain_value)
emit_move_insn (mem, fnaddr);
}
-/* Emit instruction to perform compare.
- cmp is (compare_op op0 op1). */
-static rtx
-microblaze_emit_compare (enum machine_mode mode, rtx cmp, enum rtx_code *cmp_code)
+/* Generate conditional branch -- first, generate test condition,
+ second, generate correct branch instruction. */
+
+void
+microblaze_expand_conditional_branch (enum machine_mode mode, rtx operands[])
{
- rtx cmp_op0 = XEXP (cmp, 0);
- rtx cmp_op1 = XEXP (cmp, 1);
+ enum rtx_code code = GET_CODE (operands[0]);
+ rtx cmp_op0 = operands[1];
+ rtx cmp_op1 = operands[2];
+ rtx label1 = operands[3];
rtx comp_reg = gen_reg_rtx (SImode);
- enum rtx_code code = *cmp_code;
-
+ rtx condition;
+
gcc_assert ((GET_CODE (cmp_op0) == REG) || (GET_CODE (cmp_op0) == SUBREG));
/* If comparing against zero, just test source reg. */
- if (cmp_op1 == const0_rtx)
- return cmp_op0;
+ if (cmp_op1 == const0_rtx)
+ {
+ comp_reg = cmp_op0;
+ condition = gen_rtx_fmt_ee (signed_condition (code), SImode, comp_reg, const0_rtx);
+ emit_jump_insn (gen_condjump (condition, label1));
+ }
- if (code == EQ || code == NE)
+ else if (code == EQ || code == NE)
{
/* Use xor for equal/not-equal comparison. */
emit_insn (gen_xorsi3 (comp_reg, cmp_op0, cmp_op1));
+ condition = gen_rtx_fmt_ee (signed_condition (code), SImode, comp_reg, const0_rtx);
+ emit_jump_insn (gen_condjump (condition, label1));
}
- else if (code == GT || code == GTU || code == LE || code == LEU)
- {
- /* MicroBlaze compare is not symmetrical. */
- /* Swap argument order. */
- cmp_op1 = force_reg (mode, cmp_op1);
- if (code == GT || code == LE)
- emit_insn (gen_signed_compare (comp_reg, cmp_op0, cmp_op1));
- else
- emit_insn (gen_unsigned_compare (comp_reg, cmp_op0, cmp_op1));
- /* Translate test condition. */
- *cmp_code = swap_condition (code);
- }
- else /* if (code == GE || code == GEU || code == LT || code == LTU) */
+ else
{
+ /* Generate compare and branch in single instruction. */
cmp_op1 = force_reg (mode, cmp_op1);
- if (code == GE || code == LT)
- emit_insn (gen_signed_compare (comp_reg, cmp_op1, cmp_op0));
- else
- emit_insn (gen_unsigned_compare (comp_reg, cmp_op1, cmp_op0));
+ condition = gen_rtx_fmt_ee (code, mode, cmp_op0, cmp_op1);
+ emit_jump_insn (gen_branch_compare(condition, cmp_op0, cmp_op1, label1));
}
-
- return comp_reg;
}
-/* Generate conditional branch -- first, generate test condition,
- second, generate correct branch instruction. */
-
-void
-microblaze_expand_conditional_branch (enum machine_mode mode, rtx operands[])
-{
- enum rtx_code code = GET_CODE (operands[0]);
- rtx comp;
- rtx condition;
-
- comp = microblaze_emit_compare (mode, operands[0], &code);
- condition = gen_rtx_fmt_ee (signed_condition (code), SImode, comp, const0_rtx);
- emit_jump_insn (gen_condjump (condition, operands[3]));
-}
void
microblaze_expand_conditional_branch_sf (rtx operands[])
diff --git a/gcc/config/microblaze/microblaze.md b/gcc/config/microblaze/microblaze.md
index 49d8f01..9c1e1a3 100644
--- a/gcc/config/microblaze/microblaze.md
+++ b/gcc/config/microblaze/microblaze.md
@@ -1624,28 +1624,6 @@
(set_attr "length" "4")]
)
-(define_insn "signed_compare"
- [(set (match_operand:SI 0 "register_operand" "=d")
- (unspec
- [(match_operand:SI 1 "register_operand" "d")
- (match_operand:SI 2 "register_operand" "d")] UNSPEC_CMP))]
- ""
- "cmp\t%0,%1,%2"
- [(set_attr "type" "arith")
- (set_attr "mode" "SI")
- (set_attr "length" "4")])
-
-(define_insn "unsigned_compare"
- [(set (match_operand:SI 0 "register_operand" "=d")
- (unspec
- [(match_operand:SI 1 "register_operand" "d")
- (match_operand:SI 2 "register_operand" "d")] UNSPEC_CMPU))]
- ""
- "cmpu\t%0,%1,%2"
- [(set_attr "type" "arith")
- (set_attr "mode" "SI")
- (set_attr "length" "4")])
-
;;----------------------------------------------------------------
;; Setting a register from an floating point comparison.
;;----------------------------------------------------------------
@@ -1719,6 +1697,47 @@
(set_attr "length" "4")]
)
+(define_insn "branch_compare"
+ [(set (pc)
+ (if_then_else (match_operator:SI 0 "cmp_op"
+ [(match_operand:SI 1 "register_operand" "d")
+ (match_operand:SI 2 "register_operand" "d")
+ ])
+ (label_ref (match_operand 3))
+ (pc)))
+ (clobber(reg:SI R_TMP))]
+ ""
+ {
+ operands[4] = gen_rtx_REG (SImode, MB_ABI_ASM_TEMP_REGNUM);
+ enum rtx_code code = GET_CODE (operands[0]);
+
+ if (code == GT || code == LE)
+ {
+ output_asm_insn ("cmp\tr18,%z1,%z2", operands);
+ code = swap_condition (code);
+ }
+ else if (code == GTU || code == LEU)
+ {
+ output_asm_insn ("cmpu\tr18,%z1,%z2", operands);
+ code = swap_condition (code);
+ }
+ else if (code == GE || code == LT)
+ {
+ output_asm_insn ("cmp\tr18,%z2,%z1", operands);
+ }
+ else if (code == GEU || code == LTU)
+ {
+ output_asm_insn ("cmpu\tr18,%z2,%z1", operands);
+ }
+
+ operands[0] = gen_rtx_fmt_ee (signed_condition (code), SImode, operands[4], const0_rtx);
+ return "b%C0i%?\tr18,%3";
+ }
+ [(set_attr "type" "branch")
+ (set_attr "mode" "none")
+ (set_attr "length" "12")]
+)
+
;;----------------------------------------------------------------
;; Unconditional branches
;;----------------------------------------------------------------
diff --git a/gcc/config/microblaze/predicates.md b/gcc/config/microblaze/predicates.md
index 5fd1bd4..2c23291 100644
--- a/gcc/config/microblaze/predicates.md
+++ b/gcc/config/microblaze/predicates.md
@@ -119,3 +119,7 @@
;; Test for valid PIC call operand
(define_predicate "call_insn_plt_operand"
(match_test "PLT_ADDR_P (op)"))
+
+;; Return if the code of this rtx pattern is a comparison.
+(define_predicate "cmp_op"
+ (match_code "gt,ge,gtu,geu,lt,le,ltu,leu"))
--
1.7.5.4
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