stage2 x86_64: implement integer mul

This was also an experiment to see if it were easier to implement a new
feature when using the instruction encoder.

Verdict: It's not that much easier, but I think it's certainly much more
readable, because the description of the Instruction annotates what each
field means. Right now, precise knowledge of x86_64 instructions is
still required because things like when to set the 64-bit flag, how to
read x86_64 instruction references, etc. are still not automatically
done for you.

In the future, this interface might make it sligtly easier to write an
assembler for x86_64, by abstracting the bit-fiddling aspects of
instruction encoding.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/Sema.zig b/src/Sema.zig
index 98bff5bf23..74af84b078 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -3885,6 +3885,13 @@ fn analyzeArithmetic(
                         try Module.floatSub(sema.arena, scalar_type, src, lhs_val, rhs_val);
                     break :blk val;
                 },
+                .mul => blk: {
+                    const val = if (is_int)
+                        try Module.intMul(sema.arena, lhs_val, rhs_val)
+                    else
+                        try Module.floatMul(sema.arena, scalar_type, src, lhs_val, rhs_val);
+                    break :blk val;
+                },
                 else => return sema.mod.fail(&block.base, src, "TODO Implement arithmetic operand '{s}'", .{@tagName(zir_tag)}),
             };