[gcc(refs/vendors/ventana/heads/far-branch-for-gcc11)] RISC-V: far-branch: Update branch-(not)equals-zero to support far branches

[Philipp Tomsich]

https://gcc.gnu.org/g:2df877aa80e01cec2282f27d34ef6dc0196b8297

commit 2df877aa80e01cec2282f27d34ef6dc0196b8297
Author: Philipp Tomsich <philipp.tomsich@vrull.eu>
Date:   Wed Dec 30 21:26:06 2020 +0100

    RISC-V: far-branch: Update branch-(not)equals-zero to support far branches
    
    The pattern introduced for the branch-(not)equals-zero optimisation is
    updated to support an additional clobber (this needs to be Pmode) to
    hold the jump target.
    
    gcc/ChangeLog:
    
            * config/riscv/riscv.md: Update branch-(not)equals-zero
            pattern to support far branches (i.e. larger than +/- 1MB).

Diff:
---
 gcc/config/riscv/riscv.md | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md
index 399b6fc871d..da72b2ce9fe 100644
--- a/gcc/config/riscv/riscv.md
+++ b/gcc/config/riscv/riscv.md
@@ -1868,16 +1868,22 @@
 
 ;; Conditional branches
 
-(define_insn "*branch<mode>_equals_zero"
+(define_insn "*branch<ANYI:mode><P:mode>_equals_zero"
   [(set (pc)
 	(if_then_else
 	 (match_operator 1 "equality_operator"
 			 [(match_operand:ANYI 2 "register_operand" "r")
 			  (const_int 0)])
 	 (label_ref (match_operand 0 "" ""))
-	 (pc)))]
+	 (pc)))
+   (clobber (match_scratch:P 3 "=r"))]
   "!partial_subreg_p(operands[2])"
-  "b%C1\t%2,zero,%0"
+{
+  if (get_attr_length (insn) == 12)
+    return "b%N1\t%2,zero,1f; jump\t%l0,%3; 1:";
+
+  return "b%C1\t%2,zero,%0";
+}
   [(set_attr "type" "branch")
    (set_attr "mode" "none")])