RISC-V: Add "lp64e" ABI support

Since RV32E and RV64E are now ratified, this commit prepares the ABI
support for LP64E (LP64 with reduced GPRs).

gas/ChangeLog:

	* config/tc-riscv.c (riscv_set_abi_by_arch): Update the error
	message.  (md_parse_option): Accept "lp64e".
	* doc/c-riscv.texi: Update the documentation to allow "lp64e".
	* testsuite/gas/riscv/mabi-fail-rv32e-lp64f.l:
	Change error message.
	* testsuite/gas/riscv/mabi-fail-rv32e-lp64d.l: Likewise.
	* testsuite/gas/riscv/mabi-fail-rv32e-lp64q.l: Likewise.

Author: a4lg

gas/config/tc-riscv.c

@@ -386,7 +386,7 @@ riscv_set_abi_by_arch (void)
 	as_bad ("%d-bit ABI not yet supported on %d-bit ISA", abi_xlen, xlen);
 
       if (riscv_subset_supports (&riscv_rps_as, "e") && !rve_abi)
-	as_bad ("only the ilp32e ABI is supported for e extension");
+	as_bad ("only ilp32e/lp64e ABI are supported for e extension");
 
       if (float_abi == FLOAT_ABI_SINGLE
 	  && !riscv_subset_supports (&riscv_rps_as, "f"))
@@ -3883,6 +3883,8 @@ md_parse_option (int c, const char *arg)
 	riscv_set_abi (32, FLOAT_ABI_QUAD, false);
       else if (strcmp (arg, "lp64") == 0)
 	riscv_set_abi (64, FLOAT_ABI_SOFT, false);
+      else if (strcmp (arg, "lp64e") == 0)
+	riscv_set_abi (64, FLOAT_ABI_SOFT, true);
       else if (strcmp (arg, "lp64f") == 0)
 	riscv_set_abi (64, FLOAT_ABI_SINGLE, false);
       else if (strcmp (arg, "lp64d") == 0)

gas/doc/c-riscv.texi

@@ -65,9 +65,8 @@ aren't set, then assembler will check the default configure setting
 @item -mabi=ABI
 Selects the ABI, which is either "ilp32" or "lp64", optionally followed
 by "f", "d", or "q" to indicate single-precision, double-precision, or
-quad-precision floating-point calling convention, or none to indicate
-the soft-float calling convention.  Also, "ilp32" can optionally be followed
-by "e" to indicate the RVE ABI, which is always soft-float.
+quad-precision floating-point calling convention, or none or "e" to indicate
+the soft-float calling convention ("e" indicates a soft-float RVE ABI).
 
 @cindex @samp{-mrelax} option, RISC-V
 @item -mrelax

gas/testsuite/gas/riscv/mabi-fail-rv32e-lp64d.l

@@ -1,4 +1,4 @@
 .*Assembler messages:
 .*Error: can't have 64-bit ABI on 32-bit ISA
-.*Error: only the ilp32e ABI is supported for e extension
+.*Error: only ilp32e/lp64e ABI are supported for e extension
 .*Error: ilp32d/lp64d ABI can't be used when d extension isn't supported

gas/testsuite/gas/riscv/mabi-fail-rv32e-lp64f.l

@@ -1,4 +1,4 @@
 .*Assembler messages:
 .*Error: can't have 64-bit ABI on 32-bit ISA
-.*Error: only the ilp32e ABI is supported for e extension
+.*Error: only ilp32e/lp64e ABI are supported for e extension
 .*Error: ilp32f/lp64f ABI can't be used when f extension isn't supported

gas/testsuite/gas/riscv/mabi-fail-rv32e-lp64q.l

@@ -1,4 +1,4 @@
 .*Assembler messages:
 .*Error: can't have 64-bit ABI on 32-bit ISA
-.*Error: only the ilp32e ABI is supported for e extension
+.*Error: only ilp32e/lp64e ABI are supported for e extension
 .*Error: ilp32q/lp64q ABI can't be used when q extension isn't supported