[Reassociation] Add support for reassociation with unsafe algebra.

Vector instructions are (still) not supported for either integer or floating
point.  Hopefully, that work will be landed shortly.

llvm-svn: 215647

1 files changed, 65 insertions, 0 deletions

diff --git a/llvm/test/Transforms/Reassociate/fast-ArrayOutOfBounds.ll b/llvm/test/Transforms/Reassociate/fast-ArrayOutOfBounds.ll
new file mode 100644
index 00000000000..0109e4fd1b3
--- /dev/null
+++ b/llvm/test/Transforms/Reassociate/fast-ArrayOutOfBounds.ll
@@ -0,0 +1,65 @@
+; RUN: opt < %s -reassociate -instcombine -S | FileCheck %s
+
+; Not marked as fast, so must not change.
+define float @test1(float %a0, float %a1, float %a2, float %a3, float %a4) {
+; CHECK-LABEL: test1
+; CHECK-NEXT: %tmp.2 = fadd float %a3, %a4
+; CHECK-NEXT: %tmp.4 = fadd float %tmp.2, %a2
+; CHECK-NEXT: %tmp.6 = fadd float %tmp.4, %a1
+; CHECK-NEXT: %tmp.8 = fadd float %tmp.6, %a0
+; CHECK-NEXT: %tmp.11 = fadd float %a2, %a3
+; CHECK-NEXT: %tmp.13 = fadd float %tmp.11, %a1
+; CHECK-NEXT: %tmp.15 = fadd float %tmp.13, %a0
+; CHECK-NEXT: %tmp.18 = fadd float %a1, %a2
+; CHECK-NEXT: %tmp.20 = fadd float %tmp.18, %a0
+; CHECK-NEXT: %tmp.23 = fadd float %a0, %a1
+; CHECK-NEXT: %tmp.26 = fsub float %tmp.8, %tmp.15
+; CHECK-NEXT: %tmp.28 = fadd float %tmp.20, %tmp.26
+; CHECK-NEXT: %tmp.30 = fsub float %tmp.28, %tmp.23
+; CHECK-NEXT: %tmp.32 = fsub float %tmp.30, %a4
+; CHECK-NEXT: %tmp.34 = fsub float %tmp.32, %a2
+; CHECK-NEXT: %T = fmul float %tmp.34, %tmp.34
+; CHECK-NEXT: ret float %T
+
+  %tmp.2 = fadd float %a4, %a3
+  %tmp.4 = fadd float %tmp.2, %a2
+  %tmp.6 = fadd float %tmp.4, %a1
+  %tmp.8 = fadd float %tmp.6, %a0
+  %tmp.11 = fadd float %a3, %a2
+  %tmp.13 = fadd float %tmp.11, %a1
+  %tmp.15 = fadd float %tmp.13, %a0
+  %tmp.18 = fadd float %a2, %a1
+  %tmp.20 = fadd float %tmp.18, %a0
+  %tmp.23 = fadd float %a1, %a0
+  %tmp.26 = fsub float %tmp.8, %tmp.15
+  %tmp.28 = fadd float %tmp.26, %tmp.20
+  %tmp.30 = fsub float %tmp.28, %tmp.23
+  %tmp.32 = fsub float %tmp.30, %a4
+  %tmp.34 = fsub float %tmp.32, %a2
+  %T = fmul float %tmp.34, %tmp.34
+  ret float %T
+}
+
+; Should be able to eliminate everything.
+define float @test2(float %a0, float %a1, float %a2, float %a3, float %a4) {
+; CHECK-LABEL: test2
+; CHECK: ret float 0.000000e+00
+
+  %tmp.2 = fadd fast float %a4, %a3
+  %tmp.4 = fadd fast float %tmp.2, %a2
+  %tmp.6 = fadd fast float %tmp.4, %a1
+  %tmp.8 = fadd fast float %tmp.6, %a0
+  %tmp.11 = fadd fast float %a3, %a2
+  %tmp.13 = fadd fast float %tmp.11, %a1
+  %tmp.15 = fadd fast float %tmp.13, %a0
+  %tmp.18 = fadd fast float %a2, %a1
+  %tmp.20 = fadd fast float %tmp.18, %a0
+  %tmp.23 = fadd fast float %a1, %a0
+  %tmp.26 = fsub fast float %tmp.8, %tmp.15
+  %tmp.28 = fadd fast float %tmp.26, %tmp.20
+  %tmp.30 = fsub fast float %tmp.28, %tmp.23
+  %tmp.32 = fsub fast float %tmp.30, %a4
+  %tmp.34 = fsub fast float %tmp.32, %a2
+  %T = fmul fast float %tmp.34, %tmp.34
+  ret float %T
+}