[InstCombine] Canonicalize insert splat sequences into an insert + shuffle
This adds a combine that canonicalizes a chain of inserts which broadcasts
a value into a single insert + a splat shufflevector.
This fixes PR31286.
Differential Revision: https://reviews.llvm.org/D27992
llvm-svn: 290641
diff --git a/llvm/test/Transforms/BBVectorize/loop1.ll b/llvm/test/Transforms/BBVectorize/loop1.ll
index 0a0a662..7e7b603 100644
--- a/llvm/test/Transforms/BBVectorize/loop1.ll
+++ b/llvm/test/Transforms/BBVectorize/loop1.ll
@@ -46,10 +46,10 @@
; CHECK: %add4.v.i1.1 = insertelement <2 x double> undef, double %1, i32 0
; CHECK: %add4.v.i1.2 = insertelement <2 x double> %add4.v.i1.1, double %0, i32 1
; CHECK: %add4 = fadd <2 x double> %add4.v.i1.2, %add4.v.i1.2
-; CHECK: %add5.v.i1.1 = insertelement <2 x double> undef, double %0, i32 0
-; CHECK: %add5.v.i1.2 = insertelement <2 x double> %add5.v.i1.1, double %0, i32 1
+; CHECK: %2 = insertelement <2 x double> undef, double %0, i32 0
+; CHECK: %add5.v.i1.2 = shufflevector <2 x double> %2, <2 x double> undef, <2 x i32> zeroinitializer
; CHECK: %add5 = fadd <2 x double> %add4, %add5.v.i1.2
-; CHECK: %mul6.v.i0.2 = insertelement <2 x double> %add5.v.i1.1, double %mul8, i32 1
+; CHECK: %mul6.v.i0.2 = insertelement <2 x double> %2, double %mul8, i32 1
; CHECK: %mul6 = fmul <2 x double> %mul6.v.i0.2, %add5
; CHECK: %mul6.v.r1 = extractelement <2 x double> %mul6, i32 0
; CHECK: %mul6.v.r2 = extractelement <2 x double> %mul6, i32 1