From 7ec0236fbf55939ef46662a732b00908730f826b Mon Sep 17 00:00:00 2001
From: gingerBill <bill@gingerbill.org>
Date: Thu, 26 May 2022 11:14:22 +0100
Subject: [PATCH] Add `simd_reverse`

---
 core/intrinsics/intrinsics.odin |  2 ++
 core/simd/simd.odin             |  2 ++
 src/check_builtin.cpp           | 13 +++++++++++++
 src/checker_builtin_procs.hpp   |  4 ++++
 src/llvm_backend_proc.cpp       | 16 ++++++++++++++++
 src/types.cpp                   |  2 ++
 6 files changed, 39 insertions(+)

diff --git a/core/intrinsics/intrinsics.odin b/core/intrinsics/intrinsics.odin
index 13a185da0..a14488210 100644
--- a/core/intrinsics/intrinsics.odin
+++ b/core/intrinsics/intrinsics.odin
@@ -245,6 +245,8 @@ simd_floor   :: proc(a: #simd[N]any_float) -> #simd[N]any_float ---
 simd_trunc   :: proc(a: #simd[N]any_float) -> #simd[N]any_float ---
 simd_nearest :: proc(a: #simd[N]any_float) -> #simd[N]any_float ---
 
+simd_reverse :: proc(a: #simd[N]T) -> #simd[N]T ---
+
 // WASM targets only
 wasm_memory_grow :: proc(index, delta: uintptr) -> int ---
 wasm_memory_size :: proc(index: uintptr)        -> int ---
diff --git a/core/simd/simd.odin b/core/simd/simd.odin
index 9c37c380c..060e32323 100644
--- a/core/simd/simd.odin
+++ b/core/simd/simd.odin
@@ -90,6 +90,8 @@ floor   :: intrinsics.simd_floor
 trunc   :: intrinsics.simd_trunc
 nearest :: intrinsics.simd_nearest
 
+reverse :: intrinsics.simd_reverse
+
 splat :: #force_inline proc "contextless" ($T: typeid/#simd[$LANES]$E, value: E) -> T {
 	return T{0..<LANES = value}
 }
diff --git a/src/check_builtin.cpp b/src/check_builtin.cpp
index 74c28f4d2..edf84b152 100644
--- a/src/check_builtin.cpp
+++ b/src/check_builtin.cpp
@@ -912,6 +912,19 @@ bool check_builtin_simd_operation(CheckerContext *c, Operand *operand, Ast *call
 			return true;
 		}
 
+	case BuiltinProc_simd_reverse:
+		{
+			Operand x = {};
+			check_expr(c, &x, ce->args[0]); if (x.mode == Addressing_Invalid) { return false; }
+
+			if (!is_type_simd_vector(x.type)) {
+				error(x.expr, "'%.*s' expected a simd vector type", LIT(builtin_name));
+				return false;
+			}
+			operand->type = x.type;
+			operand->mode = Addressing_Value;
+			return true;
+		}
 
 	default:
 		GB_PANIC("Unhandled simd intrinsic: %.*s", LIT(builtin_name));
diff --git a/src/checker_builtin_procs.hpp b/src/checker_builtin_procs.hpp
index adb4e4624..22ee3d141 100644
--- a/src/checker_builtin_procs.hpp
+++ b/src/checker_builtin_procs.hpp
@@ -165,6 +165,8 @@ BuiltinProc__simd_begin,
 	BuiltinProc_simd_floor,
 	BuiltinProc_simd_trunc,
 	BuiltinProc_simd_nearest,
+
+	BuiltinProc_simd_reverse,
 BuiltinProc__simd_end,
 	
 	// Platform specific intrinsics
@@ -433,6 +435,8 @@ gb_global BuiltinProc builtin_procs[BuiltinProc_COUNT] = {
 	{STR_LIT("simd_floor"), 1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("simd_trunc"), 1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT("simd_nearest"), 1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
+
+	{STR_LIT("simd_reverse"), 1, false, Expr_Expr, BuiltinProcPkg_intrinsics},
 	{STR_LIT(""), 0, false, Expr_Stmt, BuiltinProcPkg_intrinsics},
 
 
diff --git a/src/llvm_backend_proc.cpp b/src/llvm_backend_proc.cpp
index 88129ba5d..42f5a60fa 100644
--- a/src/llvm_backend_proc.cpp
+++ b/src/llvm_backend_proc.cpp
@@ -1338,6 +1338,22 @@ lbValue lb_build_builtin_simd_proc(lbProcedure *p, Ast *expr, TypeAndValue const
 			return res;
 		}
 
+	case BuiltinProc_simd_reverse:
+		{
+			i64 count = get_array_type_count(arg0.type);
+			LLVMValueRef *values = gb_alloc_array(temporary_allocator(), LLVMValueRef, count);
+			LLVMTypeRef llvm_u32 = lb_type(m, t_u32);
+			for (i64 i = 0; i < count; i++) {
+				values[i] = LLVMConstInt(llvm_u32, count-1-i, false);
+			}
+			LLVMValueRef mask = LLVMConstVector(values, cast(unsigned)count);
+
+			LLVMValueRef v = arg0.value;
+			res.value = LLVMBuildShuffleVector(p->builder, v, v, mask, "");
+			return res;
+		}
+
+
 	}
 	GB_PANIC("Unhandled simd intrinsic: '%.*s'", LIT(builtin_procs[builtin_id].name));
 
diff --git a/src/types.cpp b/src/types.cpp
index fccea2937..6f61015d3 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -1598,6 +1598,8 @@ i64 get_array_type_count(Type *t) {
 		return bt->Array.count;
 	} else if (bt->kind == Type_EnumeratedArray) {
 		return bt->EnumeratedArray.count;
+	} else if (bt->kind == Type_SimdVector) {
+		return bt->SimdVector.count;
 	}
 	GB_ASSERT(is_type_array_like(t));
 	return -1;