[clang] [llvm] [NVPTX] Fix for device function pointer having the same name as generated callprototype (PR #205639)

Daniel Donenfeld via cfe-commits cfe-commits at lists.llvm.org
Wed Jul 29 12:51:05 PDT 2026


https://github.com/daniel-donenfeld updated https://github.com/llvm/llvm-project/pull/205639

>From b772f93433fc53b6959c084014c2bbcfe8d6778f Mon Sep 17 00:00:00 2001
From: Daniel Donenfeld <ddonenfeld at nvidia.com>
Date: Tue, 2 Jun 2026 20:15:39 +0000
Subject: [PATCH 1/4] Bug fix for device function pointer having same name as a
 generated callprototype

---
 llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp       |  2 +-
 llvm/lib/Target/NVPTX/NVPTXInstrInfo.td         |  2 +-
 llvm/test/CodeGen/NVPTX/call_bitcast_byval.ll   |  2 +-
 llvm/test/CodeGen/NVPTX/callchain.ll            |  2 +-
 .../CodeGen/NVPTX/callprototype-local-label.ll  | 17 +++++++++++++++++
 .../CodeGen/NVPTX/convert-call-to-indirect.ll   | 16 ++++++++--------
 llvm/test/CodeGen/NVPTX/indirect_byval.ll       |  8 ++++----
 .../CodeGen/NVPTX/lower-args-gridconstant.ll    | 16 ++++++++--------
 llvm/test/CodeGen/NVPTX/noreturn.ll             |  4 ++--
 llvm/test/CodeGen/NVPTX/param-align.ll          | 10 +++++-----
 10 files changed, 48 insertions(+), 31 deletions(-)
 create mode 100644 llvm/test/CodeGen/NVPTX/callprototype-local-label.ll

diff --git a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
index 94acde4b22b5e..5a474e458fc14 100644
--- a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
@@ -323,7 +323,7 @@ void NVPTXAsmPrinter::emitCallPrototype(const CallBase &CB,
   const auto PtrVT = TLI->getPointerTy(DL);
   Type *RetTy = CB.getFunctionType()->getReturnType();
 
-  O << "prototype_" << UniqueCallSite << " : .callprototype ";
+  O << "$L__prototype_" << UniqueCallSite << " : .callprototype ";
 
   if (RetTy->isVoidTy()) {
     O << "()";
diff --git a/llvm/lib/Target/NVPTX/NVPTXInstrInfo.td b/llvm/lib/Target/NVPTX/NVPTXInstrInfo.td
index 65dd146926f8b..e162736cf04f3 100644
--- a/llvm/lib/Target/NVPTX/NVPTXInstrInfo.td
+++ b/llvm/lib/Target/NVPTX/NVPTXInstrInfo.td
@@ -1845,7 +1845,7 @@ foreach is_convergent = [0, 1] in {
       NVPTXInst<(outs),
                 (ins ADDR_base:$addr, CallOperand:$rets, CallOperand:$params, 
                      i32imm:$proto),
-                "call${rets:RetList} $addr, (${params:ParamList}), prototype_$proto;">;
+                "call${rets:RetList} $addr, (${params:ParamList}), $$L__prototype_$proto;">;
 
     def CALL_UNI # convergent_suffix :
       NVPTXInst<(outs),
diff --git a/llvm/test/CodeGen/NVPTX/call_bitcast_byval.ll b/llvm/test/CodeGen/NVPTX/call_bitcast_byval.ll
index 2a36c4162ba02..3cd64105b65c3 100644
--- a/llvm/test/CodeGen/NVPTX/call_bitcast_byval.ll
+++ b/llvm/test/CodeGen/NVPTX/call_bitcast_byval.ll
@@ -13,7 +13,7 @@ target triple = "nvptx64-nvidia-cuda"
 %"class.sycl::_V1::detail::half_impl::half" = type { half }
 %complex_half = type { half, half }
 
-; CHECK: prototype_0 : .callprototype (.param .align 2 .b8 _[4]) _ (.param .b32 _, .param .b32 _, .param .align 2 .b8 _[4]);
+; CHECK: $L__prototype_0 : .callprototype (.param .align 2 .b8 _[4]) _ (.param .b32 _, .param .b32 _, .param .align 2 .b8 _[4]);
 ; CHECK: .param .align 2 .b8 param2[4];
 ; CHECK: .param .align 2 .b8 retval0[4];
 ; CHECK-DAG: st.param.b16   [param2], %rs{{[0-9]+}};
diff --git a/llvm/test/CodeGen/NVPTX/callchain.ll b/llvm/test/CodeGen/NVPTX/callchain.ll
index 847d8b80ad38a..be61a9fbe3291 100644
--- a/llvm/test/CodeGen/NVPTX/callchain.ll
+++ b/llvm/test/CodeGen/NVPTX/callchain.ll
@@ -4,7 +4,7 @@
 target triple = "nvptx"
 
 define void @foo(ptr %ptr) {
-; CHECK: prototype_0 : .callprototype ()_ ()
+; CHECK: $L__prototype_0 : .callprototype ()_ ()
   tail call void %ptr()
   ret void
 }
diff --git a/llvm/test/CodeGen/NVPTX/callprototype-local-label.ll b/llvm/test/CodeGen/NVPTX/callprototype-local-label.ll
new file mode 100644
index 0000000000000..371282a28745c
--- /dev/null
+++ b/llvm/test/CodeGen/NVPTX/callprototype-local-label.ll
@@ -0,0 +1,17 @@
+; RUN: llc < %s -mtriple=nvptx64 -mcpu=sm_75 | FileCheck %s
+; RUN: %if ptxas-sm_75 %{ llc < %s -mtriple=nvptx64 -mcpu=sm_75 | %ptxas-verify --compile-only -arch=sm_75 %}
+
+target triple = "nvptx64-nvidia-cuda"
+
+ at prototype_0 = addrspace(1) global ptr null, align 8
+
+define i32 @call_via_prototype_0(i32 %a, i32 %b, i32 %c, i32 %d) {
+; CHECK-LABEL: call_via_prototype_0(
+; CHECK: ld.global.{{u|b}}64 {{%rd[0-9]+}}, [prototype_0];
+; CHECK: $L__prototype_0 : .callprototype (.param .b32 _) _ (.param .b32 _, .param .b32 _, .param .b32 _, .param .b32 _);
+; CHECK-NEXT: call (retval0), %rd{{[0-9]+}}, (param0, param1, param2, param3), $L__prototype_0;
+; CHECK-NOT: prototype_0 : .callprototype
+  %fp = load ptr, ptr addrspace(1) @prototype_0, align 8
+  %ret = call i32 %fp(i32 %a, i32 %b, i32 %c, i32 %d)
+  ret i32 %ret
+}
diff --git a/llvm/test/CodeGen/NVPTX/convert-call-to-indirect.ll b/llvm/test/CodeGen/NVPTX/convert-call-to-indirect.ll
index 1510be1b0daa9..9f763eca19915 100644
--- a/llvm/test/CodeGen/NVPTX/convert-call-to-indirect.ll
+++ b/llvm/test/CodeGen/NVPTX/convert-call-to-indirect.ll
@@ -10,7 +10,7 @@ define %struct.64 @test_return_type_mismatch(ptr %p) {
 ; CHECK-LABEL: test_return_type_mismatch(
 ; CHECK:       {
 ; CHECK-NEXT:    .reg .b64 %rd<32>;
-; CHECK-NEXT:  prototype_0 : .callprototype (.param .align 1 .b8 _[8]) _ (.param .b64 _);
+; CHECK-NEXT:    $L__prototype_0 : .callprototype (.param .align 1 .b8 _[8]) _ (.param .b64 _);
 ; CHECK-NEXT:  // %bb.0:
 ; CHECK-NEXT:    ld.param.b64 %rd1, [test_return_type_mismatch_param_0];
 ; CHECK-NEXT:    { // callseq 0, 0
@@ -18,7 +18,7 @@ define %struct.64 @test_return_type_mismatch(ptr %p) {
 ; CHECK-NEXT:    .param .align 1 .b8 retval0[8];
 ; CHECK-NEXT:    st.param.b64 [param0], %rd1;
 ; CHECK-NEXT:    mov.b64 %rd2, callee;
-; CHECK-NEXT:    call (retval0), %rd2, (param0), prototype_0;
+; CHECK-NEXT:    call (retval0), %rd2, (param0), $L__prototype_0;
 ; CHECK-NEXT:    ld.param.b8 %rd3, [retval0+7];
 ; CHECK-NEXT:    ld.param.b8 %rd4, [retval0+6];
 ; CHECK-NEXT:    ld.param.b8 %rd5, [retval0+5];
@@ -66,14 +66,14 @@ define i64 @test_param_type_mismatch(ptr %p) {
 ; CHECK-LABEL: test_param_type_mismatch(
 ; CHECK:       {
 ; CHECK-NEXT:    .reg .b64 %rd<3>;
-; CHECK-NEXT:  prototype_1 : .callprototype (.param .b64 _) _ (.param .b64 _);
+; CHECK-NEXT:    $L__prototype_1 : .callprototype (.param .b64 _) _ (.param .b64 _);
 ; CHECK-NEXT:  // %bb.0:
 ; CHECK-NEXT:    { // callseq 1, 0
 ; CHECK-NEXT:    .param .b64 param0;
 ; CHECK-NEXT:    .param .b64 retval0;
 ; CHECK-NEXT:    st.param.b64 [param0], 7;
 ; CHECK-NEXT:    mov.b64 %rd1, callee;
-; CHECK-NEXT:    call (retval0), %rd1, (param0), prototype_1;
+; CHECK-NEXT:    call (retval0), %rd1, (param0), $L__prototype_1;
 ; CHECK-NEXT:    ld.param.b64 %rd2, [retval0];
 ; CHECK-NEXT:    } // callseq 1
 ; CHECK-NEXT:    st.param.b64 [func_retval0], %rd2;
@@ -86,7 +86,7 @@ define i64 @test_param_count_mismatch(ptr %p) {
 ; CHECK-LABEL: test_param_count_mismatch(
 ; CHECK:       {
 ; CHECK-NEXT:    .reg .b64 %rd<4>;
-; CHECK-NEXT:  prototype_2 : .callprototype (.param .b64 _) _ (.param .b64 _, .param .b64 _);
+; CHECK-NEXT:    $L__prototype_2 : .callprototype (.param .b64 _) _ (.param .b64 _, .param .b64 _);
 ; CHECK-NEXT:  // %bb.0:
 ; CHECK-NEXT:    ld.param.b64 %rd1, [test_param_count_mismatch_param_0];
 ; CHECK-NEXT:    { // callseq 2, 0
@@ -96,7 +96,7 @@ define i64 @test_param_count_mismatch(ptr %p) {
 ; CHECK-NEXT:    st.param.b64 [param0], %rd1;
 ; CHECK-NEXT:    st.param.b64 [param1], 7;
 ; CHECK-NEXT:    mov.b64 %rd2, callee;
-; CHECK-NEXT:    call (retval0), %rd2, (param0, param1), prototype_2;
+; CHECK-NEXT:    call (retval0), %rd2, (param0, param1), $L__prototype_2;
 ; CHECK-NEXT:    ld.param.b64 %rd3, [retval0];
 ; CHECK-NEXT:    } // callseq 2
 ; CHECK-NEXT:    st.param.b64 [func_retval0], %rd3;
@@ -112,7 +112,7 @@ define %struct.64 @test_return_type_mismatch_variadic(ptr %p) {
 ; CHECK-NEXT:    .reg .b64 %SP;
 ; CHECK-NEXT:    .reg .b64 %SPL;
 ; CHECK-NEXT:    .reg .b64 %rd<33>;
-; CHECK-NEXT:  prototype_3 : .callprototype (.param .align 1 .b8 _[8]) _ (.param .b64 _, .param .b64 _);
+; CHECK-NEXT:    $L__prototype_3 : .callprototype (.param .align 1 .b8 _[8]) _ (.param .b64 _, .param .b64 _);
 ; CHECK-NEXT:  // %bb.0:
 ; CHECK-NEXT:    mov.b64 %SPL, __local_depot3;
 ; CHECK-NEXT:    ld.param.b64 %rd1, [test_return_type_mismatch_variadic_param_0];
@@ -124,7 +124,7 @@ define %struct.64 @test_return_type_mismatch_variadic(ptr %p) {
 ; CHECK-NEXT:    st.param.b64 [param1], %rd2;
 ; CHECK-NEXT:    st.param.b64 [param0], %rd1;
 ; CHECK-NEXT:    mov.b64 %rd3, callee_variadic;
-; CHECK-NEXT:    call (retval0), %rd3, (param0, param1), prototype_3;
+; CHECK-NEXT:    call (retval0), %rd3, (param0, param1), $L__prototype_3;
 ; CHECK-NEXT:    ld.param.b8 %rd4, [retval0+7];
 ; CHECK-NEXT:    ld.param.b8 %rd5, [retval0+6];
 ; CHECK-NEXT:    ld.param.b8 %rd6, [retval0+5];
diff --git a/llvm/test/CodeGen/NVPTX/indirect_byval.ll b/llvm/test/CodeGen/NVPTX/indirect_byval.ll
index c982aaf70d4a2..db70140c16ff4 100644
--- a/llvm/test/CodeGen/NVPTX/indirect_byval.ll
+++ b/llvm/test/CodeGen/NVPTX/indirect_byval.ll
@@ -18,7 +18,7 @@ define internal i32 @foo() {
 ; CHECK-NEXT:    .reg .b16 %rs<2>;
 ; CHECK-NEXT:    .reg .b32 %r<2>;
 ; CHECK-NEXT:    .reg .b64 %rd<4>;
-; CHECK-NEXT:  prototype_0 : .callprototype (.param .b32 _) _ (.param .align 1 .b8 _[1], .param .b64 _);
+; CHECK-NEXT:    $L__prototype_0 : .callprototype (.param .b32 _) _ (.param .align 1 .b8 _[1], .param .b64 _);
 ; CHECK-NEXT:  // %bb.0: // %entry
 ; CHECK-NEXT:    mov.b64 %SPL, __local_depot0;
 ; CHECK-NEXT:    cvta.local.u64 %SP, %SPL;
@@ -32,7 +32,7 @@ define internal i32 @foo() {
 ; CHECK-NEXT:    add.u64 %rd3, %SPL, 1;
 ; CHECK-NEXT:    ld.local.b8 %rs1, [%rd3];
 ; CHECK-NEXT:    st.param.b8 [param0], %rs1;
-; CHECK-NEXT:    call (retval0), %rd1, (param0, param1), prototype_0;
+; CHECK-NEXT:    call (retval0), %rd1, (param0, param1), $L__prototype_0;
 ; CHECK-NEXT:    ld.param.b32 %r1, [retval0];
 ; CHECK-NEXT:    } // callseq 0
 ; CHECK-NEXT:    st.param.b32 [func_retval0], %r1;
@@ -54,7 +54,7 @@ define internal i32 @bar() {
 ; CHECK-NEXT:    .reg .b64 %SPL;
 ; CHECK-NEXT:    .reg .b32 %r<2>;
 ; CHECK-NEXT:    .reg .b64 %rd<5>;
-; CHECK-NEXT:  prototype_1 : .callprototype (.param .b32 _) _ (.param .align 8 .b8 _[8], .param .b64 _);
+; CHECK-NEXT:    $L__prototype_1 : .callprototype (.param .b32 _) _ (.param .align 8 .b8 _[8], .param .b64 _);
 ; CHECK-NEXT:  // %bb.0: // %entry
 ; CHECK-NEXT:    mov.b64 %SPL, __local_depot1;
 ; CHECK-NEXT:    cvta.local.u64 %SP, %SPL;
@@ -68,7 +68,7 @@ define internal i32 @bar() {
 ; CHECK-NEXT:    add.u64 %rd3, %SPL, 8;
 ; CHECK-NEXT:    ld.local.b64 %rd4, [%rd3];
 ; CHECK-NEXT:    st.param.b64 [param0], %rd4;
-; CHECK-NEXT:    call (retval0), %rd1, (param0, param1), prototype_1;
+; CHECK-NEXT:    call (retval0), %rd1, (param0, param1), $L__prototype_1;
 ; CHECK-NEXT:    ld.param.b32 %r1, [retval0];
 ; CHECK-NEXT:    } // callseq 1
 ; CHECK-NEXT:    st.param.b32 [func_retval0], %r1;
diff --git a/llvm/test/CodeGen/NVPTX/lower-args-gridconstant.ll b/llvm/test/CodeGen/NVPTX/lower-args-gridconstant.ll
index da8c440512af3..ee4f852ca586d 100644
--- a/llvm/test/CodeGen/NVPTX/lower-args-gridconstant.ll
+++ b/llvm/test/CodeGen/NVPTX/lower-args-gridconstant.ll
@@ -122,7 +122,7 @@ define ptx_kernel void @grid_const_escape(ptr byval(%struct.s) align 4 "nvvm.gri
 ; PTX-LABEL: grid_const_escape(
 ; PTX:       {
 ; PTX-NEXT:    .reg .b64 %rd<4>;
-; PTX-NEXT:  prototype_0 : .callprototype (.param .b32 _) _ (.param .b64 _);
+; PTX-NEXT:    $L__prototype_0 : .callprototype (.param .b32 _) _ (.param .b64 _);
 ; PTX-NEXT:  // %bb.0:
 ; PTX-NEXT:    mov.b64 %rd1, grid_const_escape_param_0;
 ; PTX-NEXT:    cvta.param.u64 %rd2, %rd1;
@@ -131,7 +131,7 @@ define ptx_kernel void @grid_const_escape(ptr byval(%struct.s) align 4 "nvvm.gri
 ; PTX-NEXT:    .param .b32 retval0;
 ; PTX-NEXT:    st.param.b64 [param0], %rd2;
 ; PTX-NEXT:    mov.b64 %rd3, escape;
-; PTX-NEXT:    call (retval0), %rd3, (param0), prototype_0;
+; PTX-NEXT:    call (retval0), %rd3, (param0), $L__prototype_0;
 ; PTX-NEXT:    } // callseq 0
 ; PTX-NEXT:    ret;
 ; OPT-LABEL: define ptx_kernel void @grid_const_escape(
@@ -152,7 +152,7 @@ define ptx_kernel void @multiple_grid_const_escape(ptr byval(%struct.s) align 4
 ; PTX-NEXT:    .reg .b64 %SPL;
 ; PTX-NEXT:    .reg .b32 %r<2>;
 ; PTX-NEXT:    .reg .b64 %rd<8>;
-; PTX-NEXT:  prototype_1 : .callprototype (.param .b32 _) _ (.param .b64 _, .param .b64 _, .param .b64 _);
+; PTX-NEXT:    $L__prototype_1 : .callprototype (.param .b32 _) _ (.param .b64 _, .param .b64 _, .param .b64 _);
 ; PTX-NEXT:  // %bb.0:
 ; PTX-NEXT:    mov.b64 %SPL, __local_depot4;
 ; PTX-NEXT:    cvta.local.u64 %SP, %SPL;
@@ -173,7 +173,7 @@ define ptx_kernel void @multiple_grid_const_escape(ptr byval(%struct.s) align 4
 ; PTX-NEXT:    st.param.b64 [param1], %rd5;
 ; PTX-NEXT:    st.param.b64 [param0], %rd4;
 ; PTX-NEXT:    mov.b64 %rd7, escape3;
-; PTX-NEXT:    call (retval0), %rd7, (param0, param1, param2), prototype_1;
+; PTX-NEXT:    call (retval0), %rd7, (param0, param1, param2), $L__prototype_1;
 ; PTX-NEXT:    } // callseq 1
 ; PTX-NEXT:    ret;
 ; OPT-LABEL: define ptx_kernel void @multiple_grid_const_escape(
@@ -251,7 +251,7 @@ define ptx_kernel void @grid_const_partial_escape(ptr byval(i32) align 4 "nvvm.g
 ; PTX:       {
 ; PTX-NEXT:    .reg .b32 %r<3>;
 ; PTX-NEXT:    .reg .b64 %rd<6>;
-; PTX-NEXT:  prototype_2 : .callprototype (.param .b32 _) _ (.param .b64 _);
+; PTX-NEXT:    $L__prototype_2 : .callprototype (.param .b32 _) _ (.param .b64 _);
 ; PTX-NEXT:  // %bb.0:
 ; PTX-NEXT:    mov.b64 %rd1, grid_const_partial_escape_param_0;
 ; PTX-NEXT:    ld.param.b64 %rd2, [grid_const_partial_escape_param_1];
@@ -265,7 +265,7 @@ define ptx_kernel void @grid_const_partial_escape(ptr byval(i32) align 4 "nvvm.g
 ; PTX-NEXT:    .param .b32 retval0;
 ; PTX-NEXT:    st.param.b64 [param0], %rd4;
 ; PTX-NEXT:    mov.b64 %rd5, escape;
-; PTX-NEXT:    call (retval0), %rd5, (param0), prototype_2;
+; PTX-NEXT:    call (retval0), %rd5, (param0), $L__prototype_2;
 ; PTX-NEXT:    } // callseq 2
 ; PTX-NEXT:    ret;
 ; OPT-LABEL: define ptx_kernel void @grid_const_partial_escape(
@@ -289,7 +289,7 @@ define ptx_kernel i32 @grid_const_partial_escapemem(ptr byval(%struct.s) align 4
 ; PTX:       {
 ; PTX-NEXT:    .reg .b32 %r<4>;
 ; PTX-NEXT:    .reg .b64 %rd<6>;
-; PTX-NEXT:  prototype_3 : .callprototype (.param .b32 _) _ (.param .b64 _);
+; PTX-NEXT:    $L__prototype_3 : .callprototype (.param .b32 _) _ (.param .b64 _);
 ; PTX-NEXT:  // %bb.0:
 ; PTX-NEXT:    mov.b64 %rd1, grid_const_partial_escapemem_param_0;
 ; PTX-NEXT:    ld.param.b64 %rd2, [grid_const_partial_escapemem_param_1];
@@ -304,7 +304,7 @@ define ptx_kernel i32 @grid_const_partial_escapemem(ptr byval(%struct.s) align 4
 ; PTX-NEXT:    .param .b32 retval0;
 ; PTX-NEXT:    st.param.b64 [param0], %rd4;
 ; PTX-NEXT:    mov.b64 %rd5, escape;
-; PTX-NEXT:    call (retval0), %rd5, (param0), prototype_3;
+; PTX-NEXT:    call (retval0), %rd5, (param0), $L__prototype_3;
 ; PTX-NEXT:    } // callseq 3
 ; PTX-NEXT:    st.param.b32 [func_retval0], %r3;
 ; PTX-NEXT:    ret;
diff --git a/llvm/test/CodeGen/NVPTX/noreturn.ll b/llvm/test/CodeGen/NVPTX/noreturn.ll
index 0062e62756d36..416418c7ffde7 100644
--- a/llvm/test/CodeGen/NVPTX/noreturn.ll
+++ b/llvm/test/CodeGen/NVPTX/noreturn.ll
@@ -32,8 +32,8 @@ define ptx_kernel void @ignore_kernel_noreturn() #0 {
 }
 
 ; CHECK-LABEL: .entry callprototype_noreturn(
-; CHECK: prototype_{{[0-9]+}} : .callprototype ()_ (.param .b32 _) .noreturn;
-; CHECK: prototype_{{[0-9]+}} : .callprototype (.param .b32 _) _ (.param .b32 _);
+; CHECK: {{[$]}}L__prototype_{{[0-9]+}} : .callprototype ()_ (.param .b32 _) .noreturn;
+; CHECK: {{[$]}}L__prototype_{{[0-9]+}} : .callprototype (.param .b32 _) _ (.param .b32 _);
 
 define ptx_kernel void @callprototype_noreturn(i32) {
   %fn = load ptr, ptr addrspace(1) @function_pointer
diff --git a/llvm/test/CodeGen/NVPTX/param-align.ll b/llvm/test/CodeGen/NVPTX/param-align.ll
index c85080fdf295a..7f0a1646962ae 100644
--- a/llvm/test/CodeGen/NVPTX/param-align.ll
+++ b/llvm/test/CodeGen/NVPTX/param-align.ll
@@ -55,17 +55,17 @@ declare ptr @getfp(i32 %n)
 define ptx_device void @t6() {
 ; CHECK: .func t6
   %fp = call ptr @getfp(i32 0)
-; CHECK: prototype_2 : .callprototype ()_ (.param .align 8 .b8 _[8]);
+; CHECK: $L__prototype_2 : .callprototype ()_ (.param .align 8 .b8 _[8]);
   call void %fp(ptr byval(double) null);
 
   %fp2 = call ptr @getfp(i32 1)
-; NOALIGN4: prototype_4 : .callprototype ()_ (.param .align 2 .b8 _[4]);
-; ALIGN4: prototype_4 : .callprototype ()_ (.param .align 4 .b8 _[4]);
+; NOALIGN4: $L__prototype_4 : .callprototype ()_ (.param .align 2 .b8 _[4]);
+; ALIGN4: $L__prototype_4 : .callprototype ()_ (.param .align 4 .b8 _[4]);
   call void %fp(ptr byval(%struct.half2) null);
 
   %fp3 = call ptr @getfp(i32 2)
-; NOALIGN4: prototype_6 : .callprototype ()_ (.param .align 1 .b8 _[1]);
-; ALIGN4: prototype_6 : .callprototype ()_ (.param .align 4 .b8 _[1]);
+; NOALIGN4: $L__prototype_6 : .callprototype ()_ (.param .align 1 .b8 _[1]);
+; ALIGN4: $L__prototype_6 : .callprototype ()_ (.param .align 4 .b8 _[1]);
   call void %fp(ptr byval(i8) null);
   ret void
 }

>From af56fee30c3e08cfacdebd2ea3eba60c569dac99 Mon Sep 17 00:00:00 2001
From: Daniel Donenfeld <ddonenfeld at nvidia.com>
Date: Wed, 24 Jun 2026 21:34:42 +0000
Subject: [PATCH 2/4] Fix missed test

---
 llvm/test/CodeGen/NVPTX/vaargs.ll | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/llvm/test/CodeGen/NVPTX/vaargs.ll b/llvm/test/CodeGen/NVPTX/vaargs.ll
index ea0807a88bd68..f11c41cf68034 100644
--- a/llvm/test/CodeGen/NVPTX/vaargs.ll
+++ b/llvm/test/CodeGen/NVPTX/vaargs.ll
@@ -188,7 +188,7 @@ define i32 @test_foo(i32 %i, i64 %l, double %d, ptr %p) {
 ; CHECK32-NEXT:    .reg .b32 %SPL;
 ; CHECK32-NEXT:    .reg .b32 %r<9>;
 ; CHECK32-NEXT:    .reg .b64 %rd<3>;
-; CHECK32-NEXT:  prototype_1 : .callprototype (.param .b32 _) _ (.param .b32 _, .param .b32 _);
+; CHECK32-NEXT:  $L__prototype_1 : .callprototype (.param .b32 _) _ (.param .b32 _, .param .b32 _);
 ; CHECK32-NEXT:  // %bb.0: // %entry
 ; CHECK32-NEXT:    mov.b32 %SPL, __local_depot1;
 ; CHECK32-NEXT:    cvta.local.u32 %SP, %SPL;
@@ -211,7 +211,7 @@ define i32 @test_foo(i32 %i, i64 %l, double %d, ptr %p) {
 ; CHECK32-NEXT:    .param .b32 retval0;
 ; CHECK32-NEXT:    st.param.b32 [param1], %r7;
 ; CHECK32-NEXT:    st.param.b32 [param0], 4;
-; CHECK32-NEXT:    call (retval0), %r5, (param0, param1), prototype_1;
+; CHECK32-NEXT:    call (retval0), %r5, (param0, param1), $L__prototype_1;
 ; CHECK32-NEXT:    ld.param.b32 %r8, [retval0];
 ; CHECK32-NEXT:    } // callseq 1
 ; CHECK32-NEXT:    st.param.b32 [func_retval0], %r8;
@@ -224,7 +224,7 @@ define i32 @test_foo(i32 %i, i64 %l, double %d, ptr %p) {
 ; CHECK64-NEXT:    .reg .b64 %SPL;
 ; CHECK64-NEXT:    .reg .b32 %r<3>;
 ; CHECK64-NEXT:    .reg .b64 %rd<9>;
-; CHECK64-NEXT:  prototype_1 : .callprototype (.param .b32 _) _ (.param .b32 _, .param .b64 _);
+; CHECK64-NEXT:  $L__prototype_1 : .callprototype (.param .b32 _) _ (.param .b32 _, .param .b64 _);
 ; CHECK64-NEXT:  // %bb.0: // %entry
 ; CHECK64-NEXT:    mov.b64 %SPL, __local_depot1;
 ; CHECK64-NEXT:    cvta.local.u64 %SP, %SPL;
@@ -247,7 +247,7 @@ define i32 @test_foo(i32 %i, i64 %l, double %d, ptr %p) {
 ; CHECK64-NEXT:    .param .b32 retval0;
 ; CHECK64-NEXT:    st.param.b64 [param1], %rd8;
 ; CHECK64-NEXT:    st.param.b32 [param0], 4;
-; CHECK64-NEXT:    call (retval0), %rd6, (param0, param1), prototype_1;
+; CHECK64-NEXT:    call (retval0), %rd6, (param0, param1), $L__prototype_1;
 ; CHECK64-NEXT:    ld.param.b32 %r2, [retval0];
 ; CHECK64-NEXT:    } // callseq 1
 ; CHECK64-NEXT:    st.param.b32 [func_retval0], %r2;

>From eb992a362888de4b89e6a30525eb74178433ae8e Mon Sep 17 00:00:00 2001
From: Daniel Donenfeld <ddonenfeld at nvidia.com>
Date: Mon, 29 Jun 2026 19:54:26 +0000
Subject: [PATCH 3/4] Add cuda C++ lit test for prototype collision

---
 .../CodeGenCUDA/callprototype-local-label.cu  | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 clang/test/CodeGenCUDA/callprototype-local-label.cu

diff --git a/clang/test/CodeGenCUDA/callprototype-local-label.cu b/clang/test/CodeGenCUDA/callprototype-local-label.cu
new file mode 100644
index 0000000000000..6f4bb2de0b02a
--- /dev/null
+++ b/clang/test/CodeGenCUDA/callprototype-local-label.cu
@@ -0,0 +1,29 @@
+// REQUIRES: nvptx-registered-target
+// RUN: %clang_cc1 -triple nvptx64-nvidia-cuda -target-cpu sm_75 \
+// RUN:   -fcuda-is-device -S -o - -x cuda %s \
+// RUN:   | FileCheck %s
+
+// Test that a global named 'prototype_0' does not cause a callprototype label
+// collision: the label must be '$L__prototype_0', not 'prototype_0'.
+// extern "C" is used to keep the PTX global name unmangled.
+
+#define __device__ __attribute__((device))
+
+extern "C" {
+
+__device__ int simple_func() { return 42; }
+
+__device__ int (*prototype_0)(int, int, int, int) = nullptr;
+__device__ int call_via_prototype_0(int a, int b, int c, int d) {
+    if (prototype_0 != nullptr)
+        return prototype_0(a, b, c, d);
+    return a + b + c + d;
+}
+
+} // extern "C"
+
+// CHECK: .visible .global .align 8 .u64 prototype_0;
+// CHECK-LABEL: .visible .func  (.param .b32 func_retval0) call_via_prototype_0(
+// CHECK: $L__prototype_0 : .callprototype (.param .b32 _) _ (.param .b32 _, .param .b32 _, .param .b32 _, .param .b32 _);
+// CHECK-NEXT: call (retval0), %rd{{[0-9]+}}, (param0, param1, param2, param3), $L__prototype_0;
+// CHECK-NOT: prototype_0 : .callprototype

>From e4a8998aba70fcbbec0f22d4648c4966f8542837 Mon Sep 17 00:00:00 2001
From: Daniel Donenfeld <ddonenfeld at nvidia.com>
Date: Mon, 29 Jun 2026 20:31:48 +0000
Subject: [PATCH 4/4] Fix tests after rebase

---
 clang/test/CodeGenCUDA/callprototype-local-label.cu  | 2 +-
 llvm/test/CodeGen/NVPTX/callprototype-local-label.ll | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/clang/test/CodeGenCUDA/callprototype-local-label.cu b/clang/test/CodeGenCUDA/callprototype-local-label.cu
index 6f4bb2de0b02a..9e5f3d868a6d5 100644
--- a/clang/test/CodeGenCUDA/callprototype-local-label.cu
+++ b/clang/test/CodeGenCUDA/callprototype-local-label.cu
@@ -25,5 +25,5 @@ __device__ int call_via_prototype_0(int a, int b, int c, int d) {
 // CHECK: .visible .global .align 8 .u64 prototype_0;
 // CHECK-LABEL: .visible .func  (.param .b32 func_retval0) call_via_prototype_0(
 // CHECK: $L__prototype_0 : .callprototype (.param .b32 _) _ (.param .b32 _, .param .b32 _, .param .b32 _, .param .b32 _);
-// CHECK-NEXT: call (retval0), %rd{{[0-9]+}}, (param0, param1, param2, param3), $L__prototype_0;
+// CHECK: call (retval0), %rd{{[0-9]+}}, (param0, param1, param2, param3), $L__prototype_0;
 // CHECK-NOT: prototype_0 : .callprototype
diff --git a/llvm/test/CodeGen/NVPTX/callprototype-local-label.ll b/llvm/test/CodeGen/NVPTX/callprototype-local-label.ll
index 371282a28745c..894a5dc97d11b 100644
--- a/llvm/test/CodeGen/NVPTX/callprototype-local-label.ll
+++ b/llvm/test/CodeGen/NVPTX/callprototype-local-label.ll
@@ -7,9 +7,9 @@ target triple = "nvptx64-nvidia-cuda"
 
 define i32 @call_via_prototype_0(i32 %a, i32 %b, i32 %c, i32 %d) {
 ; CHECK-LABEL: call_via_prototype_0(
-; CHECK: ld.global.{{u|b}}64 {{%rd[0-9]+}}, [prototype_0];
 ; CHECK: $L__prototype_0 : .callprototype (.param .b32 _) _ (.param .b32 _, .param .b32 _, .param .b32 _, .param .b32 _);
-; CHECK-NEXT: call (retval0), %rd{{[0-9]+}}, (param0, param1, param2, param3), $L__prototype_0;
+; CHECK: ld.global.{{u|b}}64 {{%rd[0-9]+}}, [prototype_0];
+; CHECK: call (retval0), %rd{{[0-9]+}}, (param0, param1, param2, param3), $L__prototype_0;
 ; CHECK-NOT: prototype_0 : .callprototype
   %fp = load ptr, ptr addrspace(1) @prototype_0, align 8
   %ret = call i32 %fp(i32 %a, i32 %b, i32 %c, i32 %d)



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