From e878a6633f2447666217a5f9247af7c34507dca0 Mon Sep 17 00:00:00 2001
From: Meghan Denny <hello@nektro.net>
Date: Mon, 30 Aug 2021 00:31:40 -0700
Subject: stage2: implement runtime `%` and `@rem`

---
 src/codegen/c.zig             |  1 +
 src/codegen/llvm.zig          | 14 ++++++++++++++
 src/codegen/llvm/bindings.zig |  9 +++++++++
 3 files changed, 24 insertions(+)

(limited to 'src/codegen')

diff --git a/src/codegen/c.zig b/src/codegen/c.zig
index 2084b1e1ce..fd964f2829 100644
--- a/src/codegen/c.zig
+++ b/src/codegen/c.zig
@@ -858,6 +858,7 @@ fn genBody(o: *Object, body: []const Air.Inst.Index) error{ AnalysisFail, OutOfM
             // TODO use a different strategy for div that communicates to the optimizer
             // that wrapping is UB.
             .div           => try airBinOp( o, inst, " / "),
+            .rem           => try airBinOp( o, inst, " % "),
 
             .cmp_eq  => try airBinOp(o, inst, " == "),
             .cmp_gt  => try airBinOp(o, inst, " > "),
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index d7aa2d45b3..5d20e380b4 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -985,6 +985,7 @@ pub const FuncGen = struct {
                 .mul     => try self.airMul(inst, false),
                 .mulwrap => try self.airMul(inst, true),
                 .div     => try self.airDiv(inst),
+                .rem     => try self.airRem(inst),
                 .ptr_add => try self.airPtrAdd(inst),
                 .ptr_sub => try self.airPtrSub(inst),
 
@@ -1727,6 +1728,19 @@ pub const FuncGen = struct {
         return self.builder.buildUDiv(lhs, rhs, "");
     }
 
+    fn airRem(self: *FuncGen, inst: Air.Inst.Index) !?*const llvm.Value {
+        if (self.liveness.isUnused(inst)) return null;
+
+        const bin_op = self.air.instructions.items(.data)[inst].bin_op;
+        const lhs = try self.resolveInst(bin_op.lhs);
+        const rhs = try self.resolveInst(bin_op.rhs);
+        const inst_ty = self.air.typeOfIndex(inst);
+
+        if (inst_ty.isFloat()) return self.builder.buildFRem(lhs, rhs, "");
+        if (inst_ty.isSignedInt()) return self.builder.buildSRem(lhs, rhs, "");
+        return self.builder.buildURem(lhs, rhs, "");
+    }
+
     fn airPtrAdd(self: *FuncGen, inst: Air.Inst.Index) !?*const llvm.Value {
         if (self.liveness.isUnused(inst))
             return null;
diff --git a/src/codegen/llvm/bindings.zig b/src/codegen/llvm/bindings.zig
index d33ca29d4f..3c59fbe056 100644
--- a/src/codegen/llvm/bindings.zig
+++ b/src/codegen/llvm/bindings.zig
@@ -386,6 +386,15 @@ pub const Builder = opaque {
     pub const buildFDiv = LLVMBuildFDiv;
     extern fn LLVMBuildFDiv(*const Builder, LHS: *const Value, RHS: *const Value, Name: [*:0]const u8) *const Value;
 
+    pub const buildURem = LLVMBuildURem;
+    extern fn LLVMBuildURem(*const Builder, LHS: *const Value, RHS: *const Value, Name: [*:0]const u8) *const Value;
+
+    pub const buildSRem = LLVMBuildSRem;
+    extern fn LLVMBuildSRem(*const Builder, LHS: *const Value, RHS: *const Value, Name: [*:0]const u8) *const Value;
+
+    pub const buildFRem = LLVMBuildFRem;
+    extern fn LLVMBuildFRem(*const Builder, LHS: *const Value, RHS: *const Value, Name: [*:0]const u8) *const Value;
+
     pub const buildAnd = LLVMBuildAnd;
     extern fn LLVMBuildAnd(*const Builder, LHS: *const Value, RHS: *const Value, Name: [*:0]const u8) *const Value;
 
-- 
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