[X86] Improve the lowering of BITCAST from MVT::f64 to MVT::v4i16/MVT::v8i8.
This patch teaches the x86 backend how to efficiently lower ISD::BITCAST dag
nodes from MVT::f64 to MVT::v4i16 (and vice versa), and from MVT::f64 to
MVT::v8i8 (and vice versa).
This patch extends the logic from revision 208107 to also handle MVT::v4i16
and MVT::v8i8. Also, this patch correctly propagates Undef values when
performing the widening of a vector (example: when widening from v2i32 to
v4i32, the upper 64bits of the resulting vector are 'undef').
llvm-svn: 209451
diff --git a/llvm/test/CodeGen/X86/lower-bitcast.ll b/llvm/test/CodeGen/X86/lower-bitcast.ll
new file mode 100644
index 0000000..b9b29a5
--- /dev/null
+++ b/llvm/test/CodeGen/X86/lower-bitcast.ll
@@ -0,0 +1,155 @@
+; RUN: llc < %s -march=x86-64 -mcpu=core2 -mattr=+sse2 | FileCheck %s
+
+
+define double @test1(double %A) {
+ %1 = bitcast double %A to <2 x i32>
+ %add = add <2 x i32> %1, <i32 3, i32 5>
+ %2 = bitcast <2 x i32> %add to double
+ ret double %2
+}
+; FIXME: Ideally we should be able to fold the entire body of @test1 into a
+; single paddd instruction. At the moment we produce the sequence
+; pshufd+paddq+pshufd.
+
+; CHECK-LABEL: test1
+; CHECK-NOT: movsd
+; CHECK: pshufd
+; CHECK-NEXT: paddq
+; CHECK-NEXT: pshufd
+; CHECK-NEXT: ret
+
+
+define double @test2(double %A, double %B) {
+ %1 = bitcast double %A to <2 x i32>
+ %2 = bitcast double %B to <2 x i32>
+ %add = add <2 x i32> %1, %2
+ %3 = bitcast <2 x i32> %add to double
+ ret double %3
+}
+; FIXME: Ideally we should be able to fold the entire body of @test2 into a
+; single 'paddd %xmm1, %xmm0' instruction. At the moment we produce the
+; sequence pshufd+pshufd+paddq+pshufd.
+
+; CHECK-LABEL: test2
+; CHECK-NOT: movsd
+; CHECK: pshufd
+; CHECK-NEXT: pshufd
+; CHECK-NEXT: paddq
+; CHECK-NEXT: pshufd
+; CHECK-NEXT: ret
+
+
+define i64 @test3(i64 %A) {
+ %1 = bitcast i64 %A to <2 x float>
+ %add = fadd <2 x float> %1, <float 3.0, float 5.0>
+ %2 = bitcast <2 x float> %add to i64
+ ret i64 %2
+}
+; CHECK-LABEL: test3
+; CHECK-NOT: pshufd
+; CHECK: addps
+; CHECK-NOT: pshufd
+; CHECK: ret
+
+
+define i64 @test4(i64 %A) {
+ %1 = bitcast i64 %A to <2 x i32>
+ %add = add <2 x i32> %1, <i32 3, i32 5>
+ %2 = bitcast <2 x i32> %add to i64
+ ret i64 %2
+}
+; FIXME: At the moment we still produce the sequence pshufd+paddq+pshufd.
+; Ideally, we should fold that sequence into a single paddd.
+
+; CHECK-LABEL: test4
+; CHECK: pshufd
+; CHECK-NEXT: paddq
+; CHECK-NEXT: pshufd
+; CHECK: ret
+
+
+define double @test5(double %A) {
+ %1 = bitcast double %A to <2 x float>
+ %add = fadd <2 x float> %1, <float 3.0, float 5.0>
+ %2 = bitcast <2 x float> %add to double
+ ret double %2
+}
+; CHECK-LABEL: test5
+; CHECK: addps
+; CHECK-NEXT: ret
+
+
+define double @test6(double %A) {
+ %1 = bitcast double %A to <4 x i16>
+ %add = add <4 x i16> %1, <i16 3, i16 4, i16 5, i16 6>
+ %2 = bitcast <4 x i16> %add to double
+ ret double %2
+}
+; FIXME: Ideally we should be able to fold the entire body of @test6 into a
+; single paddw instruction.
+
+; CHECK-LABEL: test6
+; CHECK-NOT: movsd
+; CHECK: punpcklwd
+; CHECK-NEXT: paddd
+; CHECK-NEXT: pshufb
+; CHECK-NEXT: ret
+
+
+define double @test7(double %A, double %B) {
+ %1 = bitcast double %A to <4 x i16>
+ %2 = bitcast double %B to <4 x i16>
+ %add = add <4 x i16> %1, %2
+ %3 = bitcast <4 x i16> %add to double
+ ret double %3
+}
+; FIXME: Ideally we should be able to fold the entire body of @test7 into a
+; single 'paddw %xmm1, %xmm0' instruction. At the moment we produce the
+; sequence pshufd+pshufd+paddd+pshufd.
+
+; CHECK-LABEL: test7
+; CHECK-NOT: movsd
+; CHECK: punpcklwd
+; CHECK-NEXT: punpcklwd
+; CHECK-NEXT: paddd
+; CHECK-NEXT: pshufb
+; CHECK-NEXT: ret
+
+
+define double @test8(double %A) {
+ %1 = bitcast double %A to <8 x i8>
+ %add = add <8 x i8> %1, <i8 3, i8 4, i8 5, i8 6, i8 7, i8 8, i8 9, i8 10>
+ %2 = bitcast <8 x i8> %add to double
+ ret double %2
+}
+; FIXME: Ideally we should be able to fold the entire body of @test8 into a
+; single paddb instruction. At the moment we produce the sequence
+; pshufd+paddw+pshufd.
+
+; CHECK-LABEL: test8
+; CHECK-NOT: movsd
+; CHECK: punpcklbw
+; CHECK-NEXT: paddw
+; CHECK-NEXT: pshufb
+; CHECK-NEXT: ret
+
+
+define double @test9(double %A, double %B) {
+ %1 = bitcast double %A to <8 x i8>
+ %2 = bitcast double %B to <8 x i8>
+ %add = add <8 x i8> %1, %2
+ %3 = bitcast <8 x i8> %add to double
+ ret double %3
+}
+; FIXME: Ideally we should be able to fold the entire body of @test9 into a
+; single 'paddb %xmm1, %xmm0' instruction. At the moment we produce the
+; sequence pshufd+pshufd+paddw+pshufd.
+
+; CHECK-LABEL: test9
+; CHECK-NOT: movsd
+; CHECK: punpcklbw
+; CHECK-NEXT: punpcklbw
+; CHECK-NEXT: paddw
+; CHECK-NEXT: pshufb
+; CHECK-NEXT: ret
+