MIPS/GAS: Correct BFD_RELOC_MIPS16_16_PCREL_S1 fixup size

Correct the size of a BFD_RELOC_MIPS16_16_PCREL_S1 fixup made in
`md_convert_frag', fixing a bug introduced with commit c9775dde3277
("MIPS16: Add R_MIPS16_PC16_S1 branch relocation support)".  Add test
cases to verify that the overflow of this fixup's in-place addend is
still correctly detected.

	gas/
	* config/tc-mips.c (md_convert_frag): Correct
	BFD_RELOC_MIPS16_16_PCREL_S1 fixup size.
	* testsuite/gas/mips/mips16-branch-addend-4.d: New test.
	* testsuite/gas/mips/mips16-branch-addend-5.d: New test.
	* testsuite/gas/mips/mips16-branch-addend-5.l: New stderr
	output.
	* testsuite/gas/mips/mips16-branch-addend-4.s: New test source.
	* testsuite/gas/mips/mips16-branch-addend-5.s: New test source.
	* testsuite/gas/mips/mips.exp: Run the new tests.

8 files changed, 108 insertions, 5 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index f854223..a60731b 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,15 @@
+2017-04-25  Maciej W. Rozycki  <macro@imgtec.com>
+
+	* config/tc-mips.c (md_convert_frag): Correct
+	BFD_RELOC_MIPS16_16_PCREL_S1 fixup size.
+	* testsuite/gas/mips/mips16-branch-addend-4.d: New test.
+	* testsuite/gas/mips/mips16-branch-addend-5.d: New test.
+	* testsuite/gas/mips/mips16-branch-addend-5.l: New stderr
+	output.
+	* testsuite/gas/mips/mips16-branch-addend-4.s: New test source.
+	* testsuite/gas/mips/mips16-branch-addend-5.s: New test source.
+	* testsuite/gas/mips/mips.exp: Run the new tests.
+
 2017-04-25  Jose E. Marchesi  <jose.marchesi@oracle.com>
 
 	PR gas/21407
diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c
index 6a98122..da8e9ab 100644
--- a/gas/config/tc-mips.c
+++ b/gas/config/tc-mips.c
@@ -18445,15 +18445,11 @@ md_convert_frag (bfd *abfd ATTRIBUTE_UNUSED, segT asec, fragS *fragp)
 	      exp.X_add_symbol = fragp->fr_symbol;
 	      exp.X_add_number = fragp->fr_offset;
 
-	      fixp = fix_new_exp (fragp, buf - fragp->fr_literal, 2, &exp,
+	      fixp = fix_new_exp (fragp, buf - fragp->fr_literal, 4, &exp,
 				  TRUE, reloc);
 
 	      fixp->fx_file = fragp->fr_file;
 	      fixp->fx_line = fragp->fr_line;
-
-	      /* These relocations can have an addend that won't fit
-		 in 2 octets.  */
-	      fixp->fx_no_overflow = 1;
 	    }
 	  else
 	    as_bad_where (fragp->fr_file, fragp->fr_line,
diff --git a/gas/testsuite/gas/mips/mips.exp b/gas/testsuite/gas/mips/mips.exp
index f0c6c34..31a4075 100644
--- a/gas/testsuite/gas/mips/mips.exp
+++ b/gas/testsuite/gas/mips/mips.exp
@@ -1552,6 +1552,8 @@ if { [istarget mips*-*-vxworks*] } {
     run_dump_test "mips16-branch-addend-1"
     run_dump_test "mips16-branch-addend-2"
     run_dump_test "mips16-branch-addend-3"
+    run_dump_test "mips16-branch-addend-4"
+    run_dump_test "mips16-branch-addend-5"
     run_dump_test "mips16-branch-absolute"
     run_dump_test "mips16-branch-absolute-addend"
     if $has_newabi {
diff --git a/gas/testsuite/gas/mips/mips16-branch-addend-4.d b/gas/testsuite/gas/mips/mips16-branch-addend-4.d
new file mode 100644
index 0000000..273a6e1
--- /dev/null
+++ b/gas/testsuite/gas/mips/mips16-branch-addend-4.d
@@ -0,0 +1,30 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 branch relocation with addend 4
+#as: -32
+
+.*: +file format .*mips.*
+
+Disassembly of section \.text:
+	\.\.\.
+[0-9a-f]+ <[^>]*> f7ef 101f 	b	00011002 <foo\+0x10002>
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	bar
+[0-9a-f]+ <[^>]*> f7ef 601f 	bteqz	00011006 <foo\+0x10006>
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	bar
+[0-9a-f]+ <[^>]*> f7ef 611f 	btnez	0001100a <foo\+0x1000a>
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	bar
+[0-9a-f]+ <[^>]*> f7ef 221f 	beqz	v0,0001100e <foo\+0x1000e>
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	bar
+[0-9a-f]+ <[^>]*> f7ef 2a1f 	bnez	v0,00011012 <foo\+0x10012>
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	bar
+[0-9a-f]+ <[^>]*> f010 1000 	b	ffff1018 <foo\+0xffff0018>
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	bar
+[0-9a-f]+ <[^>]*> f010 6000 	bteqz	ffff101c <foo\+0xffff001c>
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	bar
+[0-9a-f]+ <[^>]*> f010 6100 	btnez	ffff1020 <foo\+0xffff0020>
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	bar
+[0-9a-f]+ <[^>]*> f010 2200 	beqz	v0,ffff1024 <foo\+0xffff0024>
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	bar
+[0-9a-f]+ <[^>]*> f010 2a00 	bnez	v0,ffff1028 <foo\+0xffff0028>
+[ 	]*[0-9a-f]+: R_MIPS16_PC16_S1	bar
+[0-9a-f]+ <[^>]*> 6500      	nop
+	\.\.\.
diff --git a/gas/testsuite/gas/mips/mips16-branch-addend-4.s b/gas/testsuite/gas/mips/mips16-branch-addend-4.s
new file mode 100644
index 0000000..5c5a7b7
--- /dev/null
+++ b/gas/testsuite/gas/mips/mips16-branch-addend-4.s
@@ -0,0 +1,24 @@
+	.text
+
+	.space	0x1000
+
+	.ent	foo
+	.set	mips16
+foo:
+	b	bar + 4 + (0x7fff << 1)
+	bteqz	bar + 4 + (0x7fff << 1)
+	btnez	bar + 4 + (0x7fff << 1)
+	beqz	$2, bar + 4 + (0x7fff << 1)
+	bnez	$2, bar + 4 + (0x7fff << 1)
+	b	bar + 4 - (0x8000 << 1)
+	bteqz	bar + 4 - (0x8000 << 1)
+	btnez	bar + 4 - (0x8000 << 1)
+	beqz	$2, bar + 4 - (0x8000 << 1)
+	bnez	$2, bar + 4 - (0x8000 << 1)
+	nop
+	.set	nomips16
+	.end	foo
+
+# Force some (non-delay-slot) zero bytes, to make 'objdump' print ...
+	.align	4, 0
+	.space	16
diff --git a/gas/testsuite/gas/mips/mips16-branch-addend-5.d b/gas/testsuite/gas/mips/mips16-branch-addend-5.d
new file mode 100644
index 0000000..47c1134
--- /dev/null
+++ b/gas/testsuite/gas/mips/mips16-branch-addend-5.d
@@ -0,0 +1,4 @@
+#objdump: -dr --prefix-addresses --show-raw-insn
+#name: MIPS16 branch relocation with addend 5
+#as: -32
+#error-output: mips16-branch-addend-5.l
diff --git a/gas/testsuite/gas/mips/mips16-branch-addend-5.l b/gas/testsuite/gas/mips/mips16-branch-addend-5.l
new file mode 100644
index 0000000..99f844e
--- /dev/null
+++ b/gas/testsuite/gas/mips/mips16-branch-addend-5.l
@@ -0,0 +1,11 @@
+.*: Assembler messages:
+.*:8: Error: relocation overflow
+.*:9: Error: relocation overflow
+.*:10: Error: relocation overflow
+.*:11: Error: relocation overflow
+.*:12: Error: relocation overflow
+.*:13: Error: relocation overflow
+.*:14: Error: relocation overflow
+.*:15: Error: relocation overflow
+.*:16: Error: relocation overflow
+.*:17: Error: relocation overflow
diff --git a/gas/testsuite/gas/mips/mips16-branch-addend-5.s b/gas/testsuite/gas/mips/mips16-branch-addend-5.s
new file mode 100644
index 0000000..aadfa19
--- /dev/null
+++ b/gas/testsuite/gas/mips/mips16-branch-addend-5.s
@@ -0,0 +1,24 @@
+	.text
+
+	.space	0x1000
+
+	.ent	foo
+	.set	mips16
+foo:
+	b	bar + 4 + (0x8000 << 1)
+	bteqz	bar + 4 + (0x8000 << 1)
+	btnez	bar + 4 + (0x8000 << 1)
+	beqz	$2, bar + 4 + (0x8000 << 1)
+	bnez	$2, bar + 4 + (0x8000 << 1)
+	b	bar + 4 - (0x8001 << 1)
+	bteqz	bar + 4 - (0x8001 << 1)
+	btnez	bar + 4 - (0x8001 << 1)
+	beqz	$2, bar + 4 - (0x8001 << 1)
+	bnez	$2, bar + 4 - (0x8001 << 1)
+	nop
+	.set	nomips16
+	.end	foo
+
+# Force some (non-delay-slot) zero bytes, to make 'objdump' print ...
+	.align	4, 0
+	.space	16