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llvm-mirror/test/CodeGen/AMDGPU/cndmask-no-def-vcc.ll
Sanjay Patel 43b7a9472e [DAG] add undef simplifications for select nodes
Sadly, this duplicates (twice) the logic from InstSimplify. There
might be some way to at least share the DAG versions of the code, 
but copying the folds seems to be the standard method to ensure 
that we don't miss these folds. 

Unlike in IR, we don't run DAGCombiner to fixpoint, so there's no 
way to ensure that we do these kinds of simplifications unless the 
code is repeated at node creation time and during combines.

There were other tests that would become worthless with this
improvement that I changed as pre-commits:
rL347161
rL347164
rL347165
rL347166
rL347167

I'm not sure how to salvage the remaining tests (diffs in this patch).
So the x86 tests verify that the new code is working as intended.
The AMDGPU test is actually similar to my motivating case: we have
some undef value that has survived to machine IR in an x86 test, and 
then it gets folded in some weird way, or we crash if we don't transfer
the undef flag. But we would have been better off never getting to that
point by doing these simplifications.

This will lead back to PR32023 someday...
https://bugs.llvm.org/show_bug.cgi?id=32023

llvm-svn: 347170
2018-11-18 17:36:23 +00:00

54 lines
1.6 KiB
LLVM

; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
declare i1 @llvm.amdgcn.class.f32(float, i32)
; Produces error after adding an implicit def to v_cndmask_b32
; GCN-LABEL: {{^}}vcc_shrink_vcc_def:
; GCN: v_cmp_eq_u32_e64 vcc, s{{[0-9]+}}, 0{{$}}
; GCN: v_cndmask_b32_e32 v{{[0-9]+}}, 1.0, v{{[0-9]+}}, vcc
define amdgpu_kernel void @vcc_shrink_vcc_def(float %arg, i32 %arg1, float %arg2, i32 %arg3) {
bb0:
%tmp = icmp sgt i32 %arg1, 4
%c = icmp eq i32 %arg3, 0
%tmp4 = select i1 %c, float %arg, float 1.000000e+00
%tmp5 = fcmp ogt float %arg2, 0.000000e+00
%tmp6 = fcmp olt float %arg2, 1.000000e+00
%tmp7 = fcmp olt float %arg, %tmp4
%tmp8 = and i1 %tmp5, %tmp6
%tmp9 = and i1 %tmp8, %tmp7
br i1 %tmp9, label %bb1, label %bb2
bb1:
store volatile i32 0, i32 addrspace(1)* undef
br label %bb2
bb2:
ret void
}
; The undef flag on the condition src must be preserved on the
; implicit vcc use to avoid verifier errors.
; GCN-LABEL: {{^}}preserve_condition_undef_flag:
; GCN-NOT: vcc
define amdgpu_kernel void @preserve_condition_undef_flag(float %arg, i32 %arg1, float %arg2) {
bb0:
%tmp = icmp sgt i32 %arg1, 4
%undef = call i1 @llvm.amdgcn.class.f32(float undef, i32 undef)
%tmp4 = select i1 %undef, float %arg, float 1.000000e+00
%tmp5 = fcmp ogt float %arg2, 0.000000e+00
%tmp6 = fcmp olt float %arg2, 1.000000e+00
%tmp7 = fcmp olt float %arg, undef
%tmp8 = and i1 %tmp5, %tmp6
%tmp9 = and i1 %tmp8, %tmp7
br i1 %tmp9, label %bb1, label %bb2
bb1:
store volatile i32 0, i32 addrspace(1)* undef
br label %bb2
bb2:
ret void
}