Commit b3c498454b6006f64aecf96b181720c524d76ae8 | zig

author	Matthew Lugg <mlugg@mlugg.co.uk> 2026-01-02 13:37:58+00:00
committer	Matthew Lugg <mlugg@mlugg.co.uk> 2026-01-03 15:45:11+00:00
log	b3c498454b6006f64aecf96b181720c524d76ae8
tree	1537f8a4d09db631191642301505510fd228c22b
parent	f7f0b9d28f2d68f40fcfe79f85b4cc37ea9ba2e8
signature	Commit is signed but in an unrecognized format.

codegen.wasm: fix 64-bit saturating shl

Previously, 64-bit '<<|' operations were emitting 64-bit shifts with one
64-bit operand and one 32-bit operand, which is illegal. Instead, as in
the lowering for regular shifts, we need to cast the RHS in this case.

1 files changed, 13 insertions(+), 2 deletions(-)

src
- codegen
  - wasm
    CodeGen.zig

src/codegen/wasm/CodeGen.zig+13-2

...	@@ -6973,9 +6973,20 @@ fn airShlSat(cg: *CodeGen, inst: Air.Inst.Index) InnerError!void {	...	@@ -6973,9 +6973,20 @@ fn airShlSat(cg: *CodeGen, inst: Air.Inst.Index) InnerError!void {
6973	return cg.fail("TODO: Saturating shifting left for integers with bitsize '{d}'", .{int_info.bits});	6973	return cg.fail("TODO: Saturating shifting left for integers with bitsize '{d}'", .{int_info.bits});
6974	}	6974	}
6975		6975
6976	const lhs = try cg.resolveInst(bin_op.lhs);
6977	const rhs = try cg.resolveInst(bin_op.rhs);
6978	const wasm_bits = toWasmBits(int_info.bits).?;	6976	const wasm_bits = toWasmBits(int_info.bits).?;
		6977
		6978	const lhs = try cg.resolveInst(bin_op.lhs);
		6979	const rhs = rhs: {
		6980	const rhs = try cg.resolveInst(bin_op.rhs);
		6981	const rhs_ty = cg.typeOf(bin_op.rhs);
		6982	// The type of `rhs` is the log2 int of the type of `lhs`, but WASM wants the lhs and rhs types to match.
		6983	if (toWasmBits(@intCast(rhs_ty.bitSize(zcu))).? == wasm_bits) {
		6984	break :rhs rhs; // the WASM types match, so no cast necessary
		6985	}
		6986	const casted = try cg.intcast(rhs, rhs_ty, ty);
		6987	break :rhs try casted.toLocal(cg, ty);
		6988	};
		6989
6979	const result = try cg.allocLocal(ty);	6990	const result = try cg.allocLocal(ty);
6980		6991
6981	if (wasm_bits == int_info.bits) {	6992	if (wasm_bits == int_info.bits) {