[PATCH v2] RISC-V: make C-extension JAL available again for (32-bit) assembly

[Jan Beulich <jbeulich@suse.com>]

Along with the normal JAL alias, the C-extension one should have been
moved as well by 839189bc932e ("RISC-V: re-arrange opcode table for
consistent alias handling"), for the assembler to actually be able to
use it where/when possible.

Since neither this nor any other compressed branch insn was being tested
so far, take the opportunity and introduce a new testcase covering those.
---
Pretty clearly this should also go on the 2.40 branch.
---
v2: Avoid re-introducing PR/gas 29940.

--- a/gas/config/tc-riscv.c
+++ b/gas/config/tc-riscv.c
@@ -2764,6 +2764,8 @@ riscv_ip (char *str, struct riscv_cl_ins
 		case 'p':
 		  goto branch;
 		case 'a':
+		  if (oparg == insn->args + 1)
+		    goto jump_check_gpr;
 		  goto jump;
 		case 'S': /* Floating-point RS1 x8-x15.  */
 		  if (!reg_lookup (&asarg, RCLASS_FPR, &regno)
@@ -3273,6 +3275,7 @@ riscv_ip (char *str, struct riscv_cl_ins
 		 but the 2nd (with 2 operands) might.  */
 	      if (oparg == insn->args)
 		{
+	    jump_check_gpr:
 		  asargStart = asarg;
 		  if (reg_lookup (&asarg, RCLASS_GPR, NULL)
 		      && (*asarg == ',' || (ISSPACE (*asarg) && asarg[1] == ',')))
--- a/opcodes/riscv-opc.c
+++ b/opcodes/riscv-opc.c
@@ -340,9 +340,9 @@ const struct riscv_opcode riscv_opcodes[
 {"jalr",        0, INSN_CLASS_I, "d,s,j",     MATCH_JALR, MASK_JALR, match_opcode, INSN_JSR },
 {"j",           0, INSN_CLASS_C, "Ca",        MATCH_C_J, MASK_C_J, match_opcode, INSN_ALIAS|INSN_BRANCH },
 {"j",           0, INSN_CLASS_I, "a",         MATCH_JAL, MASK_JAL|MASK_RD, match_opcode, INSN_ALIAS|INSN_BRANCH },
+{"jal",        32, INSN_CLASS_C, "Ca",        MATCH_C_JAL, MASK_C_JAL, match_opcode, INSN_ALIAS|INSN_JSR },
 {"jal",         0, INSN_CLASS_I, "a",         MATCH_JAL|(X_RA << OP_SH_RD), MASK_JAL|MASK_RD, match_opcode, INSN_ALIAS|INSN_JSR },
 {"jal",         0, INSN_CLASS_I, "d,a",       MATCH_JAL, MASK_JAL, match_opcode, INSN_JSR },
-{"jal",        32, INSN_CLASS_C, "Ca",        MATCH_C_JAL, MASK_C_JAL, match_opcode, INSN_ALIAS|INSN_JSR },
 {"call",        0, INSN_CLASS_I, "d,c",       (X_T1 << OP_SH_RS1), (int) M_CALL, match_never, INSN_MACRO },
 {"call",        0, INSN_CLASS_I, "c",         (X_RA << OP_SH_RS1)|(X_RA << OP_SH_RD), (int) M_CALL, match_never, INSN_MACRO },
 {"tail",        0, INSN_CLASS_I, "c",         (X_T1 << OP_SH_RS1), (int) M_CALL, match_never, INSN_MACRO },
--- /dev/null
+++ b/gas/testsuite/gas/riscv/c-branch-na.d
@@ -0,0 +1,20 @@
+#as: -march=rv32ic
+#source: c-branch.s
+#objdump: -drw -Mno-aliases
+
+.*:[ 	]+file format .*
+
+
+Disassembly of section .text:
+
+0+ <target>:
+[ 	]+[0-9a-f]+:[ 	]+c001[ 	]+c\.beqz[ 	]+s0,0 <target>[ 	]+0: R_RISCV_RVC_BRANCH	.*
+[ 	]+[0-9a-f]+:[ 	]+dcfd[ 	]+c\.beqz[ 	]+s1,0 <target>[ 	]+2: R_RISCV_RVC_BRANCH	.*
+[ 	]+[0-9a-f]+:[ 	]+fc75[ 	]+c\.bnez[ 	]+s0,0 <target>[ 	]+4: R_RISCV_RVC_BRANCH	.*
+[ 	]+[0-9a-f]+:[ 	]+fced[ 	]+c\.bnez[ 	]+s1,0 <target>[ 	]+6: R_RISCV_RVC_BRANCH	.*
+[ 	]+[0-9a-f]+:[ 	]+bfe5[ 	]+c\.j[ 	]+0 <target>[ 	]+8: R_RISCV_RVC_JUMP	.*
+[ 	]+[0-9a-f]+:[ 	]+3fdd[ 	]+c\.jal[ 	]+0 <target>[ 	]+a: R_RISCV_RVC_JUMP	.*
+[ 	]+[0-9a-f]+:[ 	]+9302[ 	]+c\.jalr[ 	]+t1
+[ 	]+[0-9a-f]+:[ 	]+8382[ 	]+c\.jr[ 	]+t2
+[ 	]+[0-9a-f]+:[ 	]+8082[ 	]+c\.jr[ 	]+ra
+#...
--- /dev/null
+++ b/gas/testsuite/gas/riscv/c-branch.d
@@ -0,0 +1,19 @@
+#as: -march=rv64ic
+#objdump: -drw
+
+.*:[ 	]+file format .*
+
+
+Disassembly of section .text:
+
+0+ <target>:
+[ 	]+[0-9a-f]+:[ 	]+c001[ 	]+beqz[ 	]+s0,0 <target>[ 	]+0: R_RISCV_RVC_BRANCH	.*
+[ 	]+[0-9a-f]+:[ 	]+dcfd[ 	]+beqz[ 	]+s1,0 <target>[ 	]+2: R_RISCV_RVC_BRANCH	.*
+[ 	]+[0-9a-f]+:[ 	]+fc75[ 	]+bnez[ 	]+s0,0 <target>[ 	]+4: R_RISCV_RVC_BRANCH	.*
+[ 	]+[0-9a-f]+:[ 	]+fced[ 	]+bnez[ 	]+s1,0 <target>[ 	]+6: R_RISCV_RVC_BRANCH	.*
+[ 	]+[0-9a-f]+:[ 	]+bfe5[ 	]+j[ 	]+0 <target>[ 	]+8: R_RISCV_RVC_JUMP	.*
+[ 	]+[0-9a-f]+:[ 	]+ff7ff0ef[ 	]+jal[ 	]+0 <target>[ 	]+a: R_RISCV_JAL	.*
+[ 	]+[0-9a-f]+:[ 	]+9302[ 	]+jalr[ 	]+t1
+[ 	]+[0-9a-f]+:[ 	]+8382[ 	]+jr[ 	]+t2
+[ 	]+[0-9a-f]+:[ 	]+8082[ 	]+ret
+#...
--- /dev/null
+++ b/gas/testsuite/gas/riscv/c-branch.s
@@ -0,0 +1,11 @@
+	.text
+target:
+	beq	x8, x0, target
+	beqz	x9, target
+	bne	x8, x0, target
+	bnez	x9, target
+	j	target
+	jal	target
+	jalr	x6
+	jr	x7
+	ret