[Mlir-commits] [mlir] [WIP][mlir][EmitC] Model lvalues as a type in EmitC (PR #91475)

[Matthias Gehre]

================
@@ -2,15 +2,15 @@
 // RUN: mlir-translate -mlir-to-cpp -declare-variables-at-top %s | FileCheck %s -check-prefix=CPP-DECLTOP
 
 func.func @emitc_variable() {
-  %c0 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> i32
-  %c1 = "emitc.variable"(){value = 42 : i32} : () -> i32
-  %c2 = "emitc.variable"(){value = -1 : i32} : () -> i32
-  %c3 = "emitc.variable"(){value = -1 : si8} : () -> si8
-  %c4 = "emitc.variable"(){value = 255 : ui8} : () -> ui8
-  %c5 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.ptr<i32>
-  %c6 = "emitc.variable"(){value = #emitc.opaque<"NULL">} : () -> !emitc.ptr<i32>
-  %c7 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.array<3x7xi32>
-  %c8 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.array<5x!emitc.ptr<i8>>
+  %c0 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<i32>
+  %c1 = "emitc.variable"(){value = 42 : i32} : () -> !emitc.lvalue<i32>
+  %c2 = "emitc.variable"(){value = -1 : i32} : () -> !emitc.lvalue<i32>
+  %c3 = "emitc.variable"(){value = -1 : si8} : () -> !emitc.lvalue<si8>
+  %c4 = "emitc.variable"(){value = 255 : ui8} : () -> !emitc.lvalue<ui8>
+  %c5 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<!emitc.ptr<i32>>
+  %c6 = "emitc.variable"(){value = #emitc.opaque<"NULL">} : () -> !emitc.lvalue<!emitc.ptr<i32>>
+  %c7 = "emitc.variable"(){value = #emitc.opaque<"">} : () -> !emitc.lvalue<!emitc.array<3x7xi32>>
----------------
mgehre-amd wrote:

Interesting question: Arrays cannot be rvalues, so maybe we don't need to wrap them? Is there any place where `!emitc.lvalue<!emitc.array>` is helpful? 
I'm thinking that we only allow arrays as function arguments, variable types and the lhs of a subscript op, there is no advantage of spelling this as `!emitc.lvalue<!emitc.array>` in all those places, or am I missing something?

https://github.com/llvm/llvm-project/pull/91475