[PowerPC] Remove redundant direct moves when extracting integers and converting to FP

This patch corresponds to review:
https://reviews.llvm.org/D21354

We use direct moves for extracting integer elements from vectors. We also use
direct moves when converting integers to FP. When these operations are chained,
we get a direct move out of a VSR followed by a direct move back into a VSR.
These are redundant - all we need to do is line up the element and convert.

llvm-svn: 275796

1 files changed, 107 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/PowerPC/remove-redundant-moves.ll b/llvm/test/CodeGen/PowerPC/remove-redundant-moves.ll
new file mode 100644
index 00000000000..6b845cbf380
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/remove-redundant-moves.ll
@@ -0,0 +1,107 @@
+; RUN: llc -mcpu=pwr8 -mtriple=powerpc64le-unknown-linux-gnu \
+; RUN:   -verify-machineinstrs < %s | FileCheck %s
+; RUN: llc -mcpu=pwr8 -mtriple=powerpc64-unknown-linux-gnu \
+; RUN:   -verify-machineinstrs < %s | FileCheck %s --check-prefix=CHECK-BE
+define double @test1(<2 x i64> %a) {
+entry:
+; CHECK-LABEL: test1
+; CHECK: xxswapd [[SW:[0-9]+]], 34
+; CHECK: xscvsxddp 1, [[SW]]
+; CHECK-BE-LABEL: test1
+; CHECK-BE: xxlor [[CP:[0-9]+]], 34, 34
+; CHECK-BE: xscvsxddp 1, [[CP]]
+  %0 = extractelement <2 x i64> %a, i32 0
+  %1 = sitofp i64 %0 to double
+  ret double %1
+}
+
+define double @test2(<2 x i64> %a) {
+entry:
+; CHECK-LABEL: test2
+; CHECK: xxlor [[CP:[0-9]+]], 34, 34
+; CHECK: xscvsxddp 1, [[CP]]
+; CHECK-BE-LABEL: test2
+; CHECK-BE: xxswapd [[SW:[0-9]+]], 34
+; CHECK-BE: xscvsxddp 1, [[SW]]
+  %0 = extractelement <2 x i64> %a, i32 1
+  %1 = sitofp i64 %0 to double
+  ret double %1
+}
+
+define float @test1f(<2 x i64> %a) {
+entry:
+; CHECK-LABEL: test1f
+; CHECK: xxswapd [[SW:[0-9]+]], 34
+; CHECK: xscvsxdsp 1, [[SW]]
+; CHECK-BE-LABEL: test1f
+; CHECK-BE: xxlor [[CP:[0-9]+]], 34, 34
+; CHECK-BE: xscvsxdsp 1, [[CP]]
+  %0 = extractelement <2 x i64> %a, i32 0
+  %1 = sitofp i64 %0 to float
+  ret float %1
+}
+
+define float @test2f(<2 x i64> %a) {
+entry:
+; CHECK-LABEL: test2f
+; CHECK: xxlor [[CP:[0-9]+]], 34, 34
+; CHECK: xscvsxdsp 1, [[CP]]
+; CHECK-BE-LABEL: test2f
+; CHECK-BE: xxswapd [[SW:[0-9]+]], 34
+; CHECK-BE: xscvsxdsp 1, [[SW]]
+  %0 = extractelement <2 x i64> %a, i32 1
+  %1 = sitofp i64 %0 to float
+  ret float %1
+}
+
+define double @test1u(<2 x i64> %a) {
+entry:
+; CHECK-LABEL: test1u
+; CHECK: xxswapd [[SW:[0-9]+]], 34
+; CHECK: xscvuxddp 1, [[SW]]
+; CHECK-BE-LABEL: test1u
+; CHECK-BE: xxlor [[CP:[0-9]+]], 34, 34
+; CHECK-BE: xscvuxddp 1, [[CP]]
+  %0 = extractelement <2 x i64> %a, i32 0
+  %1 = uitofp i64 %0 to double
+  ret double %1
+}
+
+define double @test2u(<2 x i64> %a) {
+entry:
+; CHECK-LABEL: test2u
+; CHECK: xxlor [[CP:[0-9]+]], 34, 34
+; CHECK: xscvuxddp 1, [[CP]]
+; CHECK-BE-LABEL: test2u
+; CHECK-BE: xxswapd [[SW:[0-9]+]], 34
+; CHECK-BE: xscvuxddp 1, [[SW]]
+  %0 = extractelement <2 x i64> %a, i32 1
+  %1 = uitofp i64 %0 to double
+  ret double %1
+}
+
+define float @test1fu(<2 x i64> %a) {
+entry:
+; CHECK-LABEL: test1fu
+; CHECK: xxswapd [[SW:[0-9]+]], 34
+; CHECK: xscvuxdsp 1, [[SW]]
+; CHECK-BE-LABEL: test1fu
+; CHECK-BE: xxlor [[CP:[0-9]+]], 34, 34
+; CHECK-BE: xscvuxdsp 1, [[CP]]
+  %0 = extractelement <2 x i64> %a, i32 0
+  %1 = uitofp i64 %0 to float
+  ret float %1
+}
+
+define float @test2fu(<2 x i64> %a) {
+entry:
+; CHECK-LABEL: test2fu
+; CHECK: xxlor [[CP:[0-9]+]], 34, 34
+; CHECK: xscvuxdsp 1, [[CP]]
+; CHECK-BE-LABEL: test2fu
+; CHECK-BE: xxswapd [[SW:[0-9]+]], 34
+; CHECK-BE: xscvuxdsp 1, [[SW]]
+  %0 = extractelement <2 x i64> %a, i32 1
+  %1 = uitofp i64 %0 to float
+  ret float %1
+}