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author | Chandler Carruth <chandlerc@gmail.com> | 2014-01-31 10:51:08 +0000 |
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committer | Chandler Carruth <chandlerc@gmail.com> | 2014-01-31 10:51:08 +0000 |
commit | 93228f6199694860fd824e765293718561f00136 (patch) | |
tree | d14ce9800910f99f41534aa7408572ede651dfea /test | |
parent | f0b161d7743934936ada17c06c871bceacd5767f (diff) | |
download | llvm-93228f6199694860fd824e765293718561f00136.tar.gz llvm-93228f6199694860fd824e765293718561f00136.tar.bz2 llvm-93228f6199694860fd824e765293718561f00136.tar.xz |
[vectorizer] Tweak the way we do small loop runtime unrolling in the
loop vectorizer to not do so when runtime pointer checks are needed and
share code with the new (not yet enabled) load/store saturation runtime
unrolling. Also ensure that we only consider the runtime checks when the
loop hasn't already been vectorized. If it has, the runtime check cost
has already been paid.
I've fleshed out a test case to cover the scalar unrolling as well as
the vector unrolling and comment clearly why we are or aren't following
the pattern.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200530 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test')
-rw-r--r-- | test/Transforms/LoopVectorize/X86/unroll-small-loops.ll | 57 |
1 files changed, 42 insertions, 15 deletions
diff --git a/test/Transforms/LoopVectorize/X86/unroll-small-loops.ll b/test/Transforms/LoopVectorize/X86/unroll-small-loops.ll index 1f0944d24d..d5024bb132 100644 --- a/test/Transforms/LoopVectorize/X86/unroll-small-loops.ll +++ b/test/Transforms/LoopVectorize/X86/unroll-small-loops.ll @@ -1,13 +1,26 @@ -; RUN: opt < %s -loop-vectorize -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx -force-vector-width=4 -force-vector-unroll=0 -dce -S | FileCheck %s +; RUN: opt < %s -loop-vectorize -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx -force-vector-width=4 -force-vector-unroll=0 -dce -S \ +; RUN: | FileCheck %s --check-prefix=CHECK-VECTOR +; RUN: opt < %s -loop-vectorize -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx -force-vector-width=1 -force-vector-unroll=0 -dce -S \ +; RUN: | FileCheck %s --check-prefix=CHECK-SCALAR target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" target triple = "x86_64-apple-macosx10.8.0" -;CHECK-LABEL: @foo( -;CHECK: load <4 x i32> -;CHECK-NOT: load <4 x i32> -;CHECK: store <4 x i32> -;CHECK-NOT: store <4 x i32> -;CHECK: ret + +; We don't unroll this loop because it has a small constant trip count. +; +; CHECK-VECTOR-LABEL: @foo( +; CHECK-VECTOR: load <4 x i32> +; CHECK-VECTOR-NOT: load <4 x i32> +; CHECK-VECTOR: store <4 x i32> +; CHECK-VECTOR-NOT: store <4 x i32> +; CHECK-VECTOR: ret +; +; CHECK-SCALAR-LABEL: @foo( +; CHECK-SCALAR: load i32* +; CHECK-SCALAR-NOT: load i32* +; CHECK-SCALAR: store i32 +; CHECK-SCALAR-NOT: store i32 +; CHECK-SCALAR: ret define i32 @foo(i32* nocapture %A) nounwind uwtable ssp { br label %1 @@ -26,10 +39,18 @@ define i32 @foo(i32* nocapture %A) nounwind uwtable ssp { ret i32 undef } -;CHECK-LABEL: @bar( -;CHECK: store <4 x i32> -;CHECK: store <4 x i32> -;CHECK: ret +; But this is a good small loop to unroll as we don't know of a bound on its +; trip count. +; +; CHECK-VECTOR-LABEL: @bar( +; CHECK-VECTOR: store <4 x i32> +; CHECK-VECTOR: store <4 x i32> +; CHECK-VECTOR: ret +; +; CHECK-SCALAR-LABEL: @bar( +; CHECK-SCALAR: store i32 +; CHECK-SCALAR: store i32 +; CHECK-SCALAR: ret define i32 @bar(i32* nocapture %A, i32 %n) nounwind uwtable ssp { %1 = icmp sgt i32 %n, 0 br i1 %1, label %.lr.ph, label %._crit_edge @@ -49,10 +70,16 @@ define i32 @bar(i32* nocapture %A, i32 %n) nounwind uwtable ssp { ret i32 undef } -; Also unroll if we need a runtime check. -; CHECK-LABEL: runtime_chk -; CHECK: store <4 x float> -; CHECK: store <4 x float> +; Also unroll if we need a runtime check but it was going to be added for +; vectorization anyways. +; CHECK-VECTOR-LABEL: @runtime_chk( +; CHECK-VECTOR: store <4 x float> +; CHECK-VECTOR: store <4 x float> +; +; But not if the unrolling would introduce the runtime check. +; CHECK-SCALAR-LABEL: @runtime_chk( +; CHECK-SCALAR: store float +; CHECK-SCALAR-NOT: store float define void @runtime_chk(float* %A, float* %B, float %N) { entry: br label %for.body |