[SystemZ] Use MVC for simple load/store pairs

Look for patterns of the form (store (load ...), ...) in which the two
locations are known not to partially overlap.  (Identical locations are OK.)
These sequences are better implemented by MVC unless either the load or
the store could use RELATIVE LONG instructions.

The testcase showed that we weren't using LHRL and LGHRL for extload16,
only sextloadi16.  The patch fixes that too.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185919 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 417 insertions, 0 deletions

diff --git a/test/CodeGen/SystemZ/memcpy-02.ll b/test/CodeGen/SystemZ/memcpy-02.ll
new file mode 100644
index 0000000000..0b576a713f
--- /dev/null
+++ b/test/CodeGen/SystemZ/memcpy-02.ll
@@ -0,0 +1,417 @@
+; Test load/store pairs that act as memcpys.
+;
+; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s
+
+@g1 = global i8 1
+@g2 = global i16 2
+@g3 = global i32 3
+@g4 = global i64 4
+@g5 = external global fp128, align 16
+
+; Test the simple i8 case.
+define void @f1(i8 *%ptr1) {
+; CHECK: f1:
+; CHECK: mvc 1(1,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i8 *%ptr1, i64 1
+  %val = load i8 *%ptr1
+  store i8 %val, i8 *%ptr2
+  ret void
+}
+
+; Test i8 cases where the value is zero-extended to 32 bits.
+define void @f2(i8 *%ptr1) {
+; CHECK: f2:
+; CHECK: mvc 1(1,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i8 *%ptr1, i64 1
+  %val = load i8 *%ptr1
+  %ext = zext i8 %val to i32
+  %trunc = trunc i32 %ext to i8
+  store i8 %trunc, i8 *%ptr2
+  ret void
+}
+
+; Test i8 cases where the value is zero-extended to 64 bits.
+define void @f3(i8 *%ptr1) {
+; CHECK: f3:
+; CHECK: mvc 1(1,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i8 *%ptr1, i64 1
+  %val = load i8 *%ptr1
+  %ext = zext i8 %val to i64
+  %trunc = trunc i64 %ext to i8
+  store i8 %trunc, i8 *%ptr2
+  ret void
+}
+
+; Test i8 cases where the value is sign-extended to 32 bits.
+define void @f4(i8 *%ptr1) {
+; CHECK: f4:
+; CHECK: mvc 1(1,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i8 *%ptr1, i64 1
+  %val = load i8 *%ptr1
+  %ext = sext i8 %val to i32
+  %trunc = trunc i32 %ext to i8
+  store i8 %trunc, i8 *%ptr2
+  ret void
+}
+
+; Test i8 cases where the value is sign-extended to 64 bits.
+define void @f5(i8 *%ptr1) {
+; CHECK: f5:
+; CHECK: mvc 1(1,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i8 *%ptr1, i64 1
+  %val = load i8 *%ptr1
+  %ext = sext i8 %val to i64
+  %trunc = trunc i64 %ext to i8
+  store i8 %trunc, i8 *%ptr2
+  ret void
+}
+
+; Test the simple i16 case.
+define void @f6(i16 *%ptr1) {
+; CHECK: f6:
+; CHECK: mvc 2(2,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i16 *%ptr1, i64 1
+  %val = load i16 *%ptr1
+  store i16 %val, i16 *%ptr2
+  ret void
+}
+
+; Test i16 cases where the value is zero-extended to 32 bits.
+define void @f7(i16 *%ptr1) {
+; CHECK: f7:
+; CHECK: mvc 2(2,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i16 *%ptr1, i64 1
+  %val = load i16 *%ptr1
+  %ext = zext i16 %val to i32
+  %trunc = trunc i32 %ext to i16
+  store i16 %trunc, i16 *%ptr2
+  ret void
+}
+
+; Test i16 cases where the value is zero-extended to 64 bits.
+define void @f8(i16 *%ptr1) {
+; CHECK: f8:
+; CHECK: mvc 2(2,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i16 *%ptr1, i64 1
+  %val = load i16 *%ptr1
+  %ext = zext i16 %val to i64
+  %trunc = trunc i64 %ext to i16
+  store i16 %trunc, i16 *%ptr2
+  ret void
+}
+
+; Test i16 cases where the value is sign-extended to 32 bits.
+define void @f9(i16 *%ptr1) {
+; CHECK: f9:
+; CHECK: mvc 2(2,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i16 *%ptr1, i64 1
+  %val = load i16 *%ptr1
+  %ext = sext i16 %val to i32
+  %trunc = trunc i32 %ext to i16
+  store i16 %trunc, i16 *%ptr2
+  ret void
+}
+
+; Test i16 cases where the value is sign-extended to 64 bits.
+define void @f10(i16 *%ptr1) {
+; CHECK: f10:
+; CHECK: mvc 2(2,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i16 *%ptr1, i64 1
+  %val = load i16 *%ptr1
+  %ext = sext i16 %val to i64
+  %trunc = trunc i64 %ext to i16
+  store i16 %trunc, i16 *%ptr2
+  ret void
+}
+
+; Test the simple i32 case.
+define void @f11(i32 *%ptr1) {
+; CHECK: f11:
+; CHECK: mvc 4(4,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i32 *%ptr1, i64 1
+  %val = load i32 *%ptr1
+  store i32 %val, i32 *%ptr2
+  ret void
+}
+
+; Test i32 cases where the value is zero-extended to 64 bits.
+define void @f12(i32 *%ptr1) {
+; CHECK: f12:
+; CHECK: mvc 4(4,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i32 *%ptr1, i64 1
+  %val = load i32 *%ptr1
+  %ext = zext i32 %val to i64
+  %trunc = trunc i64 %ext to i32
+  store i32 %trunc, i32 *%ptr2
+  ret void
+}
+
+; Test i32 cases where the value is sign-extended to 64 bits.
+define void @f13(i32 *%ptr1) {
+; CHECK: f13:
+; CHECK: mvc 4(4,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i32 *%ptr1, i64 1
+  %val = load i32 *%ptr1
+  %ext = sext i32 %val to i64
+  %trunc = trunc i64 %ext to i32
+  store i32 %trunc, i32 *%ptr2
+  ret void
+}
+
+; Test the i64 case.
+define void @f14(i64 *%ptr1) {
+; CHECK: f14:
+; CHECK: mvc 8(8,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i64 *%ptr1, i64 1
+  %val = load i64 *%ptr1
+  store i64 %val, i64 *%ptr2
+  ret void
+}
+
+; Test the f32 case.
+define void @f15(float *%ptr1) {
+; CHECK: f15:
+; CHECK: mvc 4(4,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr float *%ptr1, i64 1
+  %val = load float *%ptr1
+  store float %val, float *%ptr2
+  ret void
+}
+
+; Test the f64 case.
+define void @f16(double *%ptr1) {
+; CHECK: f16:
+; CHECK: mvc 8(8,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr double *%ptr1, i64 1
+  %val = load double *%ptr1
+  store double %val, double *%ptr2
+  ret void
+}
+
+; Test the f128 case.
+define void @f17(fp128 *%ptr1) {
+; CHECK: f17:
+; CHECK: mvc 16(16,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr fp128 *%ptr1, i64 1
+  %val = load fp128 *%ptr1
+  store fp128 %val, fp128 *%ptr2
+  ret void
+}
+
+; Make sure that we don't use MVC if the load is volatile.
+define void @f18(i64 *%ptr1) {
+; CHECK: f18:
+; CHECK-NOT: mvc
+; CHECK: br %r14
+  %ptr2 = getelementptr i64 *%ptr1, i64 1
+  %val = load volatile i64 *%ptr1
+  store i64 %val, i64 *%ptr2
+  ret void
+}
+
+; ...likewise the store.
+define void @f19(i64 *%ptr1) {
+; CHECK: f19:
+; CHECK-NOT: mvc
+; CHECK: br %r14
+  %ptr2 = getelementptr i64 *%ptr1, i64 1
+  %val = load i64 *%ptr1
+  store volatile i64 %val, i64 *%ptr2
+  ret void
+}
+
+; Test that MVC is used for aligned loads and stores, even if there is
+; no way of telling whether they alias.
+define void @f20(i64 *%ptr1, i64 *%ptr2) {
+; CHECK: f20:
+; CHECK: mvc 0(8,%r3), 0(%r2)
+; CHECK: br %r14
+  %val = load i64 *%ptr1
+  store i64 %val, i64 *%ptr2
+  ret void
+}
+
+; ...but if the loads aren't aligned, we can't be sure.
+define void @f21(i64 *%ptr1, i64 *%ptr2) {
+; CHECK: f21:
+; CHECK-NOT: mvc
+; CHECK: br %r14
+  %val = load i64 *%ptr1, align 2
+  store i64 %val, i64 *%ptr2, align 2
+  ret void
+}
+
+; Test a case where there is definite overlap.
+define void @f22(i64 %base) {
+; CHECK: f22:
+; CHECK-NOT: mvc
+; CHECK: br %r14
+  %add = add i64 %base, 1
+  %ptr1 = inttoptr i64 %base to i64 *
+  %ptr2 = inttoptr i64 %add to i64 *
+  %val = load i64 *%ptr1, align 1
+  store i64 %val, i64 *%ptr2, align 1
+  ret void
+}
+
+; Test that we can use MVC for global addresses for i8.
+define void @f23(i8 *%ptr) {
+; CHECK: f23:
+; CHECK: larl [[REG:%r[0-5]]], g1
+; CHECK: mvc 0(1,%r2), 0([[REG]])
+; CHECK: br %r14
+  %val = load i8 *@g1
+  store i8 %val, i8 *%ptr
+  ret void
+}
+
+; ...and again with the global on the store.
+define void @f24(i8 *%ptr) {
+; CHECK: f24:
+; CHECK: larl [[REG:%r[0-5]]], g1
+; CHECK: mvc 0(1,[[REG]]), 0(%r2)
+; CHECK: br %r14
+  %val = load i8 *%ptr
+  store i8 %val, i8 *@g1
+  ret void
+}
+
+; Test that we use LHRL for i16.
+define void @f25(i16 *%ptr) {
+; CHECK: f25:
+; CHECK: lhrl [[REG:%r[0-5]]], g2
+; CHECK: sth [[REG]], 0(%r2)
+; CHECK: br %r14
+  %val = load i16 *@g2
+  store i16 %val, i16 *%ptr
+  ret void
+}
+
+; ...likewise STHRL.
+define void @f26(i16 *%ptr) {
+; CHECK: f26:
+; CHECK: lh [[REG:%r[0-5]]], 0(%r2)
+; CHECK: sthrl [[REG]], g2
+; CHECK: br %r14
+  %val = load i16 *%ptr
+  store i16 %val, i16 *@g2
+  ret void
+}
+
+; Test that we use LRL for i32.
+define void @f27(i32 *%ptr) {
+; CHECK: f27:
+; CHECK: lrl [[REG:%r[0-5]]], g3
+; CHECK: st [[REG]], 0(%r2)
+; CHECK: br %r14
+  %val = load i32 *@g3
+  store i32 %val, i32 *%ptr
+  ret void
+}
+
+; ...likewise STRL.
+define void @f28(i32 *%ptr) {
+; CHECK: f28:
+; CHECK: l [[REG:%r[0-5]]], 0(%r2)
+; CHECK: strl [[REG]], g3
+; CHECK: br %r14
+  %val = load i32 *%ptr
+  store i32 %val, i32 *@g3
+  ret void
+}
+
+; Test that we use LGRL for i64.
+define void @f29(i64 *%ptr) {
+; CHECK: f29:
+; CHECK: lgrl [[REG:%r[0-5]]], g4
+; CHECK: stg [[REG]], 0(%r2)
+; CHECK: br %r14
+  %val = load i64 *@g4
+  store i64 %val, i64 *%ptr
+  ret void
+}
+
+; ...likewise STGRL.
+define void @f30(i64 *%ptr) {
+; CHECK: f30:
+; CHECK: lg [[REG:%r[0-5]]], 0(%r2)
+; CHECK: stgrl [[REG]], g4
+; CHECK: br %r14
+  %val = load i64 *%ptr
+  store i64 %val, i64 *@g4
+  ret void
+}
+
+; Test that we can use MVC for global addresses for fp128.
+define void @f31(fp128 *%ptr) {
+; CHECK: f31:
+; CHECK: larl [[REG:%r[0-5]]], g5
+; CHECK: mvc 0(16,%r2), 0([[REG]])
+; CHECK: br %r14
+  %val = load fp128 *@g5, align 16
+  store fp128 %val, fp128 *%ptr, align 16
+  ret void
+}
+
+; ...and again with the global on the store.
+define void @f32(fp128 *%ptr) {
+; CHECK: f32:
+; CHECK: larl [[REG:%r[0-5]]], g5
+; CHECK: mvc 0(16,[[REG]]), 0(%r2)
+; CHECK: br %r14
+  %val = load fp128 *%ptr, align 16
+  store fp128 %val, fp128 *@g5, align 16
+  ret void
+}
+
+; Test a case where offset disambiguation is enough.
+define void @f33(i64 *%ptr1) {
+; CHECK: f33:
+; CHECK: mvc 8(8,%r2), 0(%r2)
+; CHECK: br %r14
+  %ptr2 = getelementptr i64 *%ptr1, i64 1
+  %val = load i64 *%ptr1, align 1
+  store i64 %val, i64 *%ptr2, align 1
+  ret void
+}
+
+; Test f21 in cases where TBAA tells us there is no alias.
+define void @f34(i64 *%ptr1, i64 *%ptr2) {
+; CHECK: f34:
+; CHECK: mvc 0(8,%r3), 0(%r2)
+; CHECK: br %r14
+  %val = load i64 *%ptr1, align 2, !tbaa !1
+  store i64 %val, i64 *%ptr2, align 2, !tbaa !2
+  ret void
+}
+
+; Test f21 in cases where TBAA is present but doesn't help.
+define void @f35(i64 *%ptr1, i64 *%ptr2) {
+; CHECK: f35:
+; CHECK-NOT: mvc
+; CHECK: br %r14
+  %val = load i64 *%ptr1, align 2, !tbaa !1
+  store i64 %val, i64 *%ptr2, align 2, !tbaa !1
+  ret void
+}
+
+!0 = metadata !{ metadata !"root" }
+!1 = metadata !{ metadata !"set1", metadata !0 }
+!2 = metadata !{ metadata !"set2", metadata !0 }