6c2f5d6cde
Previously, if a ptr had align N, then the NVPTX lowering was taking this align N to refer to the alignment of the pointer type itself, as opposed to the alignment of the memory that it points to. As such, if a kernel with signature ``` define void @foo(ptr align 4 %_arg_ptr) ``` takes align 4 to be the alignment of the parameter, this would result in breaking the ld.param into two separate loads like so: ``` ld.param.u32 %rd1, [foo_param_0+4]; shl.b64 %rd2, %rd1, 32; ld.param.u32 %rd3, [foo_param_0]; or.b64 %rd4, %rd2, %rd3; ``` It isn't necessary as far as I can tell from the PTX ISA documents to specify the alignment of params, nor to break the loading of params into smaller loads based on their alignment. So this patch changes the codegen to the better: ``` ld.param.u64 %rd1, [foo_param_0]; ```
125 lines
3.6 KiB
LLVM
125 lines
3.6 KiB
LLVM
; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 | FileCheck %s --check-prefixes=CHECK,NOALIGN4
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; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -nvptx-force-min-byval-param-align | FileCheck %s --check-prefixes=CHECK,ALIGN4
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; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 | %ptxas-verify %}
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; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 -nvptx-force-min-byval-param-align | %ptxas-verify %}
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;;; Need 4-byte alignment on ptr passed byval
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define ptx_device void @t1(ptr byval(float) %x) {
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; CHECK: .func t1
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; CHECK: .param .align 4 .b8 t1_param_0[4]
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ret void
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}
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;;; Need 8-byte alignment on ptr passed byval
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define ptx_device void @t2(ptr byval(double) %x) {
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; CHECK: .func t2
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; CHECK: .param .align 8 .b8 t2_param_0[8]
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ret void
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}
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;;; Need 4-byte alignment on float2* passed byval
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%struct.float2 = type { float, float }
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define ptx_device void @t3(ptr byval(%struct.float2) %x) {
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; CHECK: .func t3
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; CHECK: .param .align 4 .b8 t3_param_0[8]
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ret void
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}
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define ptx_device void @t4(ptr byval(i8) %x) {
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; CHECK: .func t4
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; NOALIGN4: .param .align 1 .b8 t4_param_0[1]
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; ALIGN4: .param .align 4 .b8 t4_param_0[1]
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ret void
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}
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;;; Make sure we adjust alignment at the call site as well.
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define ptx_device void @t5(ptr align 2 byval(i8) %x) {
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; CHECK: .func t5
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; NOALIGN4: .param .align 2 .b8 t5_param_0[1]
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; ALIGN4: .param .align 4 .b8 t5_param_0[1]
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; CHECK: {
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; NOALIGN4: .param .align 1 .b8 param0[1];
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; ALIGN4: .param .align 4 .b8 param0[1];
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; CHECK: call.uni
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call void @t4(ptr byval(i8) %x)
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ret void
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}
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;;; Make sure we adjust alignment for a function prototype
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;;; in case of an inderect call.
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declare ptr @getfp(i32 %n)
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%struct.half2 = type { half, half }
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define ptx_device void @t6() {
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; CHECK: .func t6
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%fp = call ptr @getfp(i32 0)
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; CHECK: prototype_2 : .callprototype ()_ (.param .align 8 .b8 _[8]);
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call void %fp(ptr byval(double) null);
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%fp2 = call ptr @getfp(i32 1)
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; NOALIGN4: prototype_4 : .callprototype ()_ (.param .align 2 .b8 _[4]);
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; ALIGN4: prototype_4 : .callprototype ()_ (.param .align 4 .b8 _[4]);
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call void %fp(ptr byval(%struct.half2) null);
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%fp3 = call ptr @getfp(i32 2)
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; NOALIGN4: prototype_6 : .callprototype ()_ (.param .align 1 .b8 _[1]);
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; ALIGN4: prototype_6 : .callprototype ()_ (.param .align 4 .b8 _[1]);
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call void %fp(ptr byval(i8) null);
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ret void
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}
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; CHECK-LABEL: .func check_ptr_align1(
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; CHECK: ld.param.u64 %rd1, [check_ptr_align1_param_0];
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; CHECK-NOT: ld.param.u8
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; CHECK: mov.b32 %r1, 0;
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; CHECK: st.u8 [%rd1+3], %r1;
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; CHECK: st.u8 [%rd1+2], %r1;
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; CHECK: st.u8 [%rd1+1], %r1;
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; CHECK: mov.b32 %r2, 1;
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; CHECK: st.u8 [%rd1], %r2;
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; CHECK: ret;
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define void @check_ptr_align1(ptr align 1 %_arg_ptr) {
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entry:
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store i32 1, ptr %_arg_ptr, align 1
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ret void
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}
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; CHECK-LABEL: .func check_ptr_align2(
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; CHECK: ld.param.u64 %rd1, [check_ptr_align2_param_0];
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; CHECK-NOT: ld.param.u16
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; CHECK: mov.b32 %r1, 0;
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; CHECK: st.u16 [%rd1+2], %r1;
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; CHECK: mov.b32 %r2, 2;
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; CHECK: st.u16 [%rd1], %r2;
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; CHECK: ret;
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define void @check_ptr_align2(ptr align 2 %_arg_ptr) {
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entry:
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store i32 2, ptr %_arg_ptr, align 2
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ret void
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}
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; CHECK-LABEL: .func check_ptr_align4(
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; CHECK: ld.param.u64 %rd1, [check_ptr_align4_param_0];
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; CHECK-NOT: ld.param.u32
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; CHECK: mov.b32 %r1, 4;
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; CHECK: st.u32 [%rd1], %r1;
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; CHECK: ret;
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define void @check_ptr_align4(ptr align 4 %_arg_ptr) {
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entry:
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store i32 4, ptr %_arg_ptr, align 4
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ret void
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}
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; CHECK-LABEL: .func check_ptr_align8(
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; CHECK: ld.param.u64 %rd1, [check_ptr_align8_param_0];
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; CHECK: mov.b32 %r1, 8;
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; CHECK: st.u32 [%rd1], %r1;
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; CHECK: ret;
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define void @check_ptr_align8(ptr align 8 %_arg_ptr) {
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entry:
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store i32 8, ptr %_arg_ptr, align 8
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ret void
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}
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