Fixes for bitcast bugs with LLVM 17 / opaque pointers (JuliaLang#54548)

Skip setName on folded inputs, and ensure
the correct pointer address space is used.

src/intrinsics.cpp

@@ -638,9 +638,21 @@ static jl_cgval_t generic_bitcast(jl_codectx_t &ctx, ArrayRef<jl_cgval_t> argv)
             if (isa<Instruction>(vx) && !vx->hasName())
                 // emit_inttoptr may undo an PtrToInt
                 setName(ctx.emission_context, vx, "bitcast_coercion");
+        } else if (vxt->isPointerTy() && llvmt->isPointerTy()) {
+            // emit_bitcast preserves the origin address space, which we can't have here
+            #if JL_LLVM_VERSION >= 170000
+            vx = ctx.builder.CreateAddrSpaceCast(vx, llvmt);
+            #else
+            vx = ctx.builder.CreatePointerBitCastOrAddrSpaceCast(vx, llvmt);
+            #endif
+            if (isa<Instruction>(vx) && !vx->hasName())
+                // cast may have been folded
+                setName(ctx.emission_context, vx, "bitcast_coercion");
         } else {
             vx = emit_bitcast(ctx, vx, llvmt);
-            setName(ctx.emission_context, vx, "bitcast_coercion");
+            if (isa<Instruction>(vx) && !vx->hasName())
+                // emit_bitcast may undo another bitcast
+                setName(ctx.emission_context, vx, "bitcast_coercion");
         }
     }
 

test/intrinsics.jl

@@ -345,3 +345,16 @@ Base.show(io::IO, a::IntWrap) = print(io, "IntWrap(", a.x, ")")
         @test r2 isa IntWrap && r2.x === 103 === r[].x && r2 !== r[]
     end
 end)()
+
+@testset "issue #54548" begin
+    @inline passthrough(ptr::Core.LLVMPtr{T,A}) where {T,A} = Base.llvmcall(("""
+            define ptr addrspace(1) @entry(ptr addrspace(1) %0) #0 {
+            entry:
+                ret ptr addrspace(1) %0
+            }
+
+            attributes #0 = { alwaysinline }""", "entry"),
+        Core.LLVMPtr{T,A}, Tuple{Core.LLVMPtr{T,A}}, ptr)
+    f(gws) = passthrough(Core.bitcast(Core.LLVMPtr{UInt32,1}, gws))
+    f(C_NULL)
+end