diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6453b26584b..d4d61a0cdba 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2018-03-01  Palmer Dabbelt  <palmer@sifive.com>
+
+	* config/riscv/riscv.opt (mrelax): New option.
+	* config/riscv/riscv.c (riscv_file_start): Emit ".option
+	"norelax" when riscv_mrelax is disabled.
+	* doc/invoke.texi (RISC-V): Document "-mrelax" and "-mno-relax".
+
 2018-03-13  Aaron Sawdey  <acsawdey@linux.vnet.ibm.com>
 
 	PR target/84743
diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c
index c38f6c394d5..3e81874de23 100644
--- a/gcc/config/riscv/riscv.c
+++ b/gcc/config/riscv/riscv.c
@@ -3979,6 +3979,11 @@ riscv_file_start (void)
 
   /* Instruct GAS to generate position-[in]dependent code.  */
   fprintf (asm_out_file, "\t.option %spic\n", (flag_pic ? "" : "no"));
+
+  /* If the user specifies "-mno-relax" on the command line then disable linker
+     relaxation in the assembler.  */
+  if (! riscv_mrelax)
+    fprintf (asm_out_file, "\t.option norelax\n");
 }
 
 /* Implement TARGET_ASM_OUTPUT_MI_THUNK.  Generate rtl rather than asm text
diff --git a/gcc/config/riscv/riscv.opt b/gcc/config/riscv/riscv.opt
index 581a26bb5c1..b37ac75d9bb 100644
--- a/gcc/config/riscv/riscv.opt
+++ b/gcc/config/riscv/riscv.opt
@@ -106,6 +106,11 @@ mexplicit-relocs
 Target Report Mask(EXPLICIT_RELOCS)
 Use %reloc() operators, rather than assembly macros, to load addresses.
 
+mrelax
+Target Bool Var(riscv_mrelax) Init(1)
+Take advantage of linker relaxations to reduce the number of instructions
+required to materialize symbol addresses.
+
 Mask(64BIT)
 
 Mask(MUL)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 5d383509797..4d543008f53 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -1042,7 +1042,8 @@ See RS/6000 and PowerPC Options.
 -msave-restore  -mno-save-restore @gol
 -mstrict-align -mno-strict-align @gol
 -mcmodel=medlow -mcmodel=medany @gol
--mexplicit-relocs  -mno-explicit-relocs @gol}
+-mexplicit-relocs  -mno-explicit-relocs @gol
+-mrelax -mno-relax @gol}
 
 @emph{RL78 Options}
 @gccoptlist{-msim  -mmul=none  -mmul=g13  -mmul=g14  -mallregs @gol
@@ -23102,6 +23103,12 @@ Use or do not use assembler relocation operators when dealing with symbolic
 addresses.  The alternative is to use assembler macros instead, which may
 limit optimization.
 
+@item -mrelax
+@itemx -mno-relax
+Take advantage of linker relaxations to reduce the number of instructions
+required to materialize symbol addresses. The default is to take advantage of
+linker relaxations.
+
 @end table
 
 @node RL78 Options