Merge remote-tracking branch 'remotes/palmer/tags/riscv-for-master-4.0-rc1' into staging

A Single RISC-V Patch for 4.0-rc1

If this is too late I'm OK with it being in rc2, but it fixes a concrete
regression and nobody has complained yet so I'd prefer it to be in rc1
if possible.

The fix is to zero-extend the inputs to DIVUW and REMUW, which was
exposed by the GCC test suite.

# gpg: Signature made Tue 26 Mar 2019 05:54:20 GMT
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# gpg:                issuer "palmer@dabbelt.com"
# gpg: Good signature from "Palmer Dabbelt <palmer@dabbelt.com>" [unknown]
# gpg:                 aka "Palmer Dabbelt <palmer@sifive.com>" [unknown]
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* remotes/palmer/tags/riscv-for-master-4.0-rc1:
  target/riscv: Zero extend the inputs of divuw and remuw
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target/riscv/insn_trans/trans_rvm.inc.c

@@ -103,7 +103,7 @@ static bool trans_divw(DisasContext *ctx, arg_divw *a)
 static bool trans_divuw(DisasContext *ctx, arg_divuw *a)
 {
     REQUIRE_EXT(ctx, RVM);
-    return gen_arith_div_w(ctx, a, &gen_divu);
+    return gen_arith_div_uw(ctx, a, &gen_divu);
 }
 
 static bool trans_remw(DisasContext *ctx, arg_remw *a)
@@ -115,6 +115,6 @@ static bool trans_remw(DisasContext *ctx, arg_remw *a)
 static bool trans_remuw(DisasContext *ctx, arg_remuw *a)
 {
     REQUIRE_EXT(ctx, RVM);
-    return gen_arith_div_w(ctx, a, &gen_remu);
+    return gen_arith_div_uw(ctx, a, &gen_remu);
 }
 #endif

target/riscv/translate.c

@@ -600,6 +600,27 @@ static bool gen_arith_div_w(DisasContext *ctx, arg_r *a,
     return true;
 }
 
+static bool gen_arith_div_uw(DisasContext *ctx, arg_r *a,
+                            void(*func)(TCGv, TCGv, TCGv))
+{
+    TCGv source1, source2;
+    source1 = tcg_temp_new();
+    source2 = tcg_temp_new();
+
+    gen_get_gpr(source1, a->rs1);
+    gen_get_gpr(source2, a->rs2);
+    tcg_gen_ext32u_tl(source1, source1);
+    tcg_gen_ext32u_tl(source2, source2);
+
+    (*func)(source1, source1, source2);
+
+    tcg_gen_ext32s_tl(source1, source1);
+    gen_set_gpr(a->rd, source1);
+    tcg_temp_free(source1);
+    tcg_temp_free(source2);
+    return true;
+}
+
 #endif
 
 static bool gen_arith(DisasContext *ctx, arg_r *a,