[PATCH] Fix riscv malloc error on small alignment after norvc.

[Jim Wilson <jimw at sifive dot com>]

Without this patch, on the included testcase, we get

rohan:2035$ bin/riscv32-unknown-elf-as align-1.s 
align-1.s: Assembler messages:
align-1.s:3: Fatal error: can't extend frag 18446744073709551614 chars
rohan:2036$ 

because the code is trying to malloc (unsigned long)-2 bytes.  This is fixed
with an early out exit because no alignment nops are required in this case.

This also adds a new testcase, and simplifies the riscv gas testsuite logic
a little.

Tested with binutils make check on riscv32-elf and riscv64-elf.  There were
no regressions.  Committed.

Jim

	gas/
	* config/tc-riscv.c (riscv_frag_align_code): New local insn_alignment.
	Early return if bytes less than or equal to insn_alignment.
	* testsuite/gas/riscv/align-1.l: New.
	* testsuite/gas/riscv/align-1.s: New.
	* testsuite/gas/riscv/riscv.exp: Use run_dump_tests.  Use run_list_test
	for align-1.
---
 gas/config/tc-riscv.c             | 12 ++++++++++--
 gas/testsuite/gas/riscv/align-1.l |  1 +
 gas/testsuite/gas/riscv/align-1.s |  3 +++
 gas/testsuite/gas/riscv/riscv.exp | 11 ++---------
 4 files changed, 16 insertions(+), 11 deletions(-)
 create mode 100644 gas/testsuite/gas/riscv/align-1.l
 create mode 100644 gas/testsuite/gas/riscv/align-1.s

diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
index 8bb400e100..c2e5f30e50 100644
--- a/gas/config/tc-riscv.c
+++ b/gas/config/tc-riscv.c
@@ -2319,10 +2319,18 @@ bfd_boolean
 riscv_frag_align_code (int n)
 {
   bfd_vma bytes = (bfd_vma) 1 << n;
-  bfd_vma worst_case_bytes = bytes - (riscv_opts.rvc ? 2 : 4);
-  char *nops = frag_more (worst_case_bytes);
+  bfd_vma insn_alignment = riscv_opts.rvc ? 2 : 4;
+  bfd_vma worst_case_bytes = bytes - insn_alignment;
+  char *nops;
   expressionS ex;
 
+  /* If we are moving to a smaller alignment than the instruction size, then no
+     alignment is required. */
+  if (bytes <= insn_alignment)
+    return TRUE;
+
+  nops = frag_more (worst_case_bytes);
+
   /* When not relaxing, riscv_handle_align handles code alignment.  */
   if (!riscv_opts.relax)
     return FALSE;
diff --git a/gas/testsuite/gas/riscv/align-1.l b/gas/testsuite/gas/riscv/align-1.l
new file mode 100644
index 0000000000..8ea739b764
--- /dev/null
+++ b/gas/testsuite/gas/riscv/align-1.l
@@ -0,0 +1 @@
+# No warning or error expected.
diff --git a/gas/testsuite/gas/riscv/align-1.s b/gas/testsuite/gas/riscv/align-1.s
new file mode 100644
index 0000000000..ee6a94dea7
--- /dev/null
+++ b/gas/testsuite/gas/riscv/align-1.s
@@ -0,0 +1,3 @@
+	.option norvc
+	.align 2
+	.align 1
diff --git a/gas/testsuite/gas/riscv/riscv.exp b/gas/testsuite/gas/riscv/riscv.exp
index 5ef92f5006..162c77d96a 100644
--- a/gas/testsuite/gas/riscv/riscv.exp
+++ b/gas/testsuite/gas/riscv/riscv.exp
@@ -19,13 +19,6 @@
 # MA 02110-1301, USA.
 
 if [istarget riscv*-*-*] {
-    run_dump_test "t_insns"
-    run_dump_test "fmv.x"
-    run_dump_test "c-lui-fail"
-    run_dump_test "c-addi4spn-fail"
-    run_dump_test "c-addi16sp-fail"
-    run_dump_test "satp"
-    run_dump_test "eh-relocs"
-    run_dump_test "c-lw"
-    run_dump_test "c-ld"
+    run_dump_tests [lsort [glob -nocomplain $srcdir/$subdir/*.d]]
+    run_list_test "align-1"
 }
-- 
2.14.1