From 803178353976fe4ef343aef25dfa6d8e418ef88f Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Wed, 8 Dec 2021 19:09:37 -0700
Subject: [PATCH] stage1: fix regression of shift by negative value error

The previous commit (38b2d6209239f0dad7cb38e656d9d38506f126ca) regressed
the compile error test case for when doing saturating shift left of a
comptime-known negative RHS.

This commit additionally fixes the error for regular shifts in addition
to saturating shifts.
---
 src/stage1/ir.cpp       | 32 ++++++++++++++++++++++++--------
 test/compile_errors.zig |  6 +++---
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/src/stage1/ir.cpp b/src/stage1/ir.cpp
index 5cec62bc80..34ff4a4f04 100644
--- a/src/stage1/ir.cpp
+++ b/src/stage1/ir.cpp
@@ -10121,6 +10121,30 @@ static Stage1AirInst *ir_analyze_bit_shift(IrAnalyze *ira, Stage1ZirInstBinOp *b
         if (op2_val == nullptr)
             return ira->codegen->invalid_inst_gen;
 
+        if (op2_val->type->id == ZigTypeIdVector) {
+            expand_undef_array(ira->codegen, op2_val);
+            size_t len = op2_val->type->data.vector.len;
+            for (size_t i = 0; i < len; i += 1) {
+                ZigValue *scalar_val = &op2_val->data.x_array.data.s_none.elements[i];
+                if (scalar_val->data.x_bigint.is_negative) {
+                    Buf *val_buf = buf_alloc();
+                    bigint_append_buf(val_buf, &scalar_val->data.x_bigint, 10);
+                    ir_add_error(ira, casted_op2,
+                        buf_sprintf("shift by negative value %s at vector index %zu",
+                            buf_ptr(val_buf), i));
+                    return ira->codegen->invalid_inst_gen;
+                }
+            }
+        } else {
+            if (op2_val->data.x_bigint.is_negative) {
+                Buf *val_buf = buf_alloc();
+                bigint_append_buf(val_buf, &op2_val->data.x_bigint, 10);
+                ir_add_error(ira, casted_op2,
+                    buf_sprintf("shift by negative value %s", buf_ptr(val_buf)));
+                return ira->codegen->invalid_inst_gen;
+            }
+        }
+
         if (value_cmp_numeric_val_all(op2_val, CmpEQ, nullptr))
             return ir_analyze_cast(ira, bin_op_instruction->base.scope, bin_op_instruction->base.source_node, op1->value->type, op1);
     }
@@ -10515,14 +10539,6 @@ static Stage1AirInst *ir_analyze_bin_op_math(IrAnalyze *ira, Stage1ZirInstBinOp
                     return ira->codegen->invalid_inst_gen;
                 }
             }
-        } else if (op_id == IrBinOpShlSat) {
-            if (op2_val->data.x_bigint.is_negative) {
-                Buf *val_buf = buf_alloc();
-                bigint_append_buf(val_buf, &op2_val->data.x_bigint, 10);
-                ir_add_error(ira, casted_op2,
-                    buf_sprintf("shift by negative value %s", buf_ptr(val_buf)));
-                return ira->codegen->invalid_inst_gen;
-            }
         }
 
         return ir_analyze_math_op(ira, instruction->base.scope, instruction->base.source_node, resolved_type, op1_val, op_id, op2_val);
diff --git a/test/compile_errors.zig b/test/compile_errors.zig
index 7df818a708..c3de643e12 100644
--- a/test/compile_errors.zig
+++ b/test/compile_errors.zig
@@ -8913,7 +8913,7 @@ pub fn addCases(ctx: *TestContext) !void {
     });
 
     ctx.objErrStage1("saturating arithmetic does not allow floats",
-        \\pub fn main() !void {
+        \\export fn a() void {
         \\    _ = @as(f32, 1.0) +| @as(f32, 1.0);
         \\}
     , &[_][]const u8{
@@ -8921,7 +8921,7 @@ pub fn addCases(ctx: *TestContext) !void {
     });
 
     ctx.objErrStage1("saturating shl does not allow negative rhs at comptime",
-        \\pub fn main() !void {
+        \\export fn a() void {
         \\    _ = @as(i32, 1) <<| @as(i32, -2);
         \\}
     , &[_][]const u8{
@@ -8929,7 +8929,7 @@ pub fn addCases(ctx: *TestContext) !void {
     });
 
     ctx.objErrStage1("saturating shl assign does not allow negative rhs at comptime",
-        \\pub fn main() !void {
+        \\export fn a() void {
         \\    comptime {
         \\      var x = @as(i32, 1);
         \\      x <<|= @as(i32, -2);