Only construct legal int types during alloc opt.

When promoting heap to stack allocations, make sure we only emit legal
integer allocas by checking with the module's datalayout. X86 doesn't
seem to care, but back-ends like SPIR-V don't know how to handle
arbitrarily-sized integers.

Fixes JuliaGPU/oneAPI.jl#55

Author: maleadt

src/llvm-alloc-opt.cpp

@@ -936,7 +936,12 @@ void Optimizer::moveToStack(CallInst *orig_inst, size_t sz, bool has_ref)
         ptr = cast<Instruction>(prolog_builder.CreateBitCast(buff, pass.T_pint8));
     }
     else {
-        buff = prolog_builder.CreateAlloca(Type::getIntNTy(pass.getLLVMContext(), sz * 8));
+        Type *buffty;
+        if (pass.DL->isLegalInteger(sz * 8))
+            buffty = Type::getIntNTy(pass.getLLVMContext(), sz * 8);
+        else
+            buffty = ArrayType::get(Type::getInt8Ty(pass.getLLVMContext()), sz);
+        buff = prolog_builder.CreateAlloca(buffty);
         buff->setAlignment(Align(align));
         ptr = cast<Instruction>(prolog_builder.CreateBitCast(buff, pass.T_pint8));
     }
@@ -1193,8 +1198,10 @@ void Optimizer::splitOnStack(CallInst *orig_inst)
         else if (field.elty && !field.multiloc) {
             allocty = field.elty;
         }
-        else {
+        else if (pass.DL->isLegalInteger(field.size * 8)) {
             allocty = Type::getIntNTy(pass.getLLVMContext(), field.size * 8);
+        } else {
+            allocty = ArrayType::get(Type::getInt8Ty(pass.getLLVMContext()), field.size);
         }
         slot.slot = prolog_builder.CreateAlloca(allocty);
         insertLifetime(prolog_builder.CreateBitCast(slot.slot, pass.T_pint8),

test/llvmpasses/alloc-opt2.jl

@@ -79,12 +79,30 @@ L3:
 """)
 # CHECK-LABEL: }{{$}}
 
+# CHECK-LABEL: @legal_int_types
+# CHECK: alloca [12 x i8]
+# CHECK-NOT: alloca i96
+# CHECK: ret void
+println("""
+define void @legal_int_types() {
+  %ptls = call {}*** @julia.ptls_states()
+  %ptls_i8 = bitcast {}*** %ptls to i8*
+  %var1 = call {} addrspace(10)* @julia.gc_alloc_obj(i8* %ptls_i8, $isz 12, {} addrspace(10)* @tag)
+  %var2 = addrspacecast {} addrspace(10)* %var1 to {} addrspace(11)*
+  %var3 = call {}* @julia.pointer_from_objref({} addrspace(11)* %var2)
+  ret void
+}
+""")
+# CHECK-LABEL: }{{$}}
+
+
+
 println("""
 declare void @external_function()
 declare {} addrspace(10)* @external_function2()
 declare {}*** @julia.ptls_states()
 declare noalias {} addrspace(10)* @julia.gc_alloc_obj(i8*, $isz, {} addrspace(10)*)
-declare i64 @julia.pointer_from_objref({} addrspace(11)*)
+declare {}* @julia.pointer_from_objref({} addrspace(11)*)
 declare void @llvm.memcpy.p11i8.p0i8.i64(i8 addrspace(11)* nocapture writeonly, i8* nocapture readonly, i64, i32, i1)
 declare token @llvm.julia.gc_preserve_begin(...)
 declare void @llvm.julia.gc_preserve_end(token)