SLPVectorization: Add a basic support for cross-basic block slp vectorization.

We collect gather sequences when we vectorize basic blocks. Gather sequences are excellent
hints for vectorization of other basic blocks.

llvm-svn: 184444

1 files changed, 54 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SLPVectorizer/X86/cross_block_slp.ll b/llvm/test/Transforms/SLPVectorizer/X86/cross_block_slp.ll
new file mode 100644
index 00000000000..8246453519b
--- /dev/null
+++ b/llvm/test/Transforms/SLPVectorizer/X86/cross_block_slp.ll
@@ -0,0 +1,54 @@
+; RUN: opt < %s -basicaa -slp-vectorizer -dce -S -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx | FileCheck %s
+
+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"
+
+; int foo(double *A, float *B, int g) {
+;   float B0 = B[0];
+;   float B1 = B[1]; <----- BasicBlock #1
+;   B0 += 5;
+;   B1 += 8;
+;
+;   if (g) bar();
+;
+;   A[0] += B0;     <------- BasicBlock #3
+;   A[1] += B1;
+; }
+
+
+;CHECK: @foo
+;CHECK: load <2 x float>
+;CHECK: fadd <2 x float>
+;CHECK: call i32
+;CHECK: load <2 x double>
+;CHECK: fadd <2 x double>
+;CHECK: store <2 x double>
+;CHECK: ret
+define i32 @foo(double* nocapture %A, float* nocapture %B, i32 %g) {
+entry:
+  %0 = load float* %B, align 4
+  %arrayidx1 = getelementptr inbounds float* %B, i64 1
+  %1 = load float* %arrayidx1, align 4
+  %add = fadd float %0, 5.000000e+00
+  %add2 = fadd float %1, 8.000000e+00
+  %tobool = icmp eq i32 %g, 0
+  br i1 %tobool, label %if.end, label %if.then
+
+if.then:
+  %call = tail call i32 (...)* @bar()
+  br label %if.end
+
+if.end:
+  %conv = fpext float %add to double
+  %2 = load double* %A, align 8
+  %add4 = fadd double %conv, %2
+  store double %add4, double* %A, align 8
+  %conv5 = fpext float %add2 to double
+  %arrayidx6 = getelementptr inbounds double* %A, i64 1
+  %3 = load double* %arrayidx6, align 8
+  %add7 = fadd double %conv5, %3
+  store double %add7, double* %arrayidx6, align 8
+  ret i32 undef
+}
+
+declare i32 @bar(...)