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| author | Matthias Braun <matze@braunis.de> | 2016-05-06 22:43:50 +0000 |
|---|---|---|
| committer | Matthias Braun <matze@braunis.de> | 2016-05-06 22:43:50 +0000 |
| commit | 22152acf7b5d05bea25672cf5eb287893f85fa41 (patch) | |
| tree | b63055c92cb79b4cc8fda611ccd4988f6112a62a /llvm/test/CodeGen/AMDGPU/detect-dead-lanes.mir | |
| parent | 8f429ead58999e584d6857ebc334564f88489de0 (diff) | |
| download | bcm5719-llvm-22152acf7b5d05bea25672cf5eb287893f85fa41.tar.gz bcm5719-llvm-22152acf7b5d05bea25672cf5eb287893f85fa41.zip | |
DetectDeadLanes: Increase precision when detecting undef inputs
In case of COPY-like instruction we may be able to deduce that a certain
input is unused, based on the used lanes of the register defined by the
instruction.
This even works accross otherwise incompatible copies (no need to have
compatible lanemasks, completely unused operands are still completely
unused). It even makes sense to redo the analysis in this case since we
gained information for a case we previously stopped at because of the
incompatible masks.
llvm-svn: 268815
Diffstat (limited to 'llvm/test/CodeGen/AMDGPU/detect-dead-lanes.mir')
| -rw-r--r-- | llvm/test/CodeGen/AMDGPU/detect-dead-lanes.mir | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/llvm/test/CodeGen/AMDGPU/detect-dead-lanes.mir b/llvm/test/CodeGen/AMDGPU/detect-dead-lanes.mir index d04b3f13e3f..8c761298cd2 100644 --- a/llvm/test/CodeGen/AMDGPU/detect-dead-lanes.mir +++ b/llvm/test/CodeGen/AMDGPU/detect-dead-lanes.mir @@ -5,6 +5,7 @@ define void @test2() { ret void } define void @test3() { ret void } define void @test4() { ret void } + define void @test5() { ret void } define void @loop0() { ret void } define void @loop1() { ret void } define void @loop2() { ret void } @@ -20,7 +21,7 @@ # CHECK: S_NOP 0, implicit %3:sub1 # CHECK: S_NOP 0, implicit undef %3:sub2 # CHECK: %4 = COPY %3:sub0_sub1 -# CHECK: %5 = COPY %3:sub2_sub3 +# CHECK: %5 = COPY undef %3:sub2_sub3 # CHECK: S_NOP 0, implicit %4:sub0 # CHECK: S_NOP 0, implicit %4:sub1 # CHECK: S_NOP 0, implicit undef %5:sub0 @@ -255,6 +256,25 @@ body: | S_NOP 0, implicit %1 ... --- +# Check that unused inputs are marked as undef, even if the vreg itself is +# used. +# CHECK-LABEL: name: test5 +# CHECK: S_NOP 0, implicit-def %0 +# CHECK: %1 = REG_SEQUENCE undef %0, {{[0-9]+}}, %0, {{[0-9]+}} +# CHECK: S_NOP 0, implicit %1:sub1 +name: test5 +isSSA: true +tracksRegLiveness: true +registers: + - { id: 0, class: sreg_32 } + - { id: 1, class: sreg_64 } +body: | + bb.0: + S_NOP 0, implicit-def %0 + %1 = REG_SEQUENCE %0, %subreg.sub0, %0, %subreg.sub1 + S_NOP 0, implicit %1:sub1 +... +--- # Check "optimistic" dataflow fixpoint in phi-loops. # CHECK-LABEL: name: loop0 # CHECK: bb.0: |
