[AArch64] Enable more load clustering in the MI Scheduler.

This patch adds unscaled loads and sign-extend loads to the TII
getMemOpBaseRegImmOfs API, which is used to control clustering in the MI
scheduler. This is done to create more opportunities for load pairing.  I've
also added the scaled LDRSWui instruction, which was missing from the scaled
instructions. Finally, I've added support in shouldClusterLoads for clustering
adjacent sext and zext loads that too can be paired by the load/store optimizer.

Differential Revision: http://reviews.llvm.org/D18048

llvm-svn: 263819

1 files changed, 99 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/AArch64/arm64-ldp-cluster.ll b/llvm/test/CodeGen/AArch64/arm64-ldp-cluster.ll
new file mode 100644
index 00000000000..0d659eb0a4b
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/arm64-ldp-cluster.ll
@@ -0,0 +1,99 @@
+; REQUIRES: asserts
+; RUN: llc < %s -mtriple=arm64-linux-gnu -mcpu=cortex-a57 -verify-misched -debug-only=misched -o - 2>&1 > /dev/null | FileCheck %s
+
+; Test ldr clustering.
+; CHECK: ********** MI Scheduling **********
+; CHECK-LABEL: ldr_int:BB#0
+; CHECK: Cluster loads SU(1) - SU(2)
+; CHECK: SU(1):   %vreg{{[0-9]+}}<def> = LDRWui
+; CHECK: SU(2):   %vreg{{[0-9]+}}<def> = LDRWui
+define i32 @ldr_int(i32* %a) nounwind {
+  %p1 = getelementptr inbounds i32, i32* %a, i32 1
+  %tmp1 = load i32, i32* %p1, align 2
+  %p2 = getelementptr inbounds i32, i32* %a, i32 2
+  %tmp2 = load i32, i32* %p2, align 2
+  %tmp3 = add i32 %tmp1, %tmp2
+  ret i32 %tmp3
+}
+
+; Test ldpsw clustering
+; CHECK: ********** MI Scheduling **********
+; CHECK-LABEL: ldp_sext_int:BB#0
+; CHECK: Cluster loads SU(1) - SU(2)
+; CHECK: SU(1):   %vreg{{[0-9]+}}<def> = LDRSWui
+; CHECK: SU(2):   %vreg{{[0-9]+}}<def> = LDRSWui
+define i64 @ldp_sext_int(i32* %p) nounwind {
+  %tmp = load i32, i32* %p, align 4
+  %add.ptr = getelementptr inbounds i32, i32* %p, i64 1
+  %tmp1 = load i32, i32* %add.ptr, align 4
+  %sexttmp = sext i32 %tmp to i64
+  %sexttmp1 = sext i32 %tmp1 to i64
+  %add = add nsw i64 %sexttmp1, %sexttmp
+  ret i64 %add
+}
+
+; Test ldur clustering.
+; CHECK: ********** MI Scheduling **********
+; CHECK-LABEL: ldur_int:BB#0
+; CHECK: Cluster loads SU(2) - SU(1)
+; CHECK: SU(1):   %vreg{{[0-9]+}}<def> = LDURWi
+; CHECK: SU(2):   %vreg{{[0-9]+}}<def> = LDURWi
+define i32 @ldur_int(i32* %a) nounwind {
+  %p1 = getelementptr inbounds i32, i32* %a, i32 -1
+  %tmp1 = load i32, i32* %p1, align 2
+  %p2 = getelementptr inbounds i32, i32* %a, i32 -2
+  %tmp2 = load i32, i32* %p2, align 2
+  %tmp3 = add i32 %tmp1, %tmp2
+  ret i32 %tmp3
+}
+
+; Test sext + zext clustering.
+; CHECK: ********** MI Scheduling **********
+; CHECK-LABEL: ldp_half_sext_zext_int:BB#0
+; CHECK: Cluster loads SU(3) - SU(4)
+; CHECK: SU(3):   %vreg{{[0-9]+}}<def> = LDRSWui
+; CHECK: SU(4):   %vreg{{[0-9]+}}:sub_32<def,read-undef> = LDRWui
+define i64 @ldp_half_sext_zext_int(i64* %q, i32* %p) nounwind {
+  %tmp0 = load i64, i64* %q, align 4
+  %tmp = load i32, i32* %p, align 4
+  %add.ptr = getelementptr inbounds i32, i32* %p, i64 1
+  %tmp1 = load i32, i32* %add.ptr, align 4
+  %sexttmp = sext i32 %tmp to i64
+  %sexttmp1 = zext i32 %tmp1 to i64
+  %add = add nsw i64 %sexttmp1, %sexttmp
+  %add1 = add nsw i64 %add, %tmp0
+  ret i64 %add1
+}
+
+; Test zext + sext clustering.
+; CHECK: ********** MI Scheduling **********
+; CHECK-LABEL: ldp_half_zext_sext_int:BB#0
+; CHECK: Cluster loads SU(3) - SU(4)
+; CHECK: SU(3):   %vreg{{[0-9]+}}:sub_32<def,read-undef> = LDRWui
+; CHECK: SU(4):   %vreg{{[0-9]+}}<def> = LDRSWui
+define i64 @ldp_half_zext_sext_int(i64* %q, i32* %p) nounwind {
+  %tmp0 = load i64, i64* %q, align 4
+  %tmp = load i32, i32* %p, align 4
+  %add.ptr = getelementptr inbounds i32, i32* %p, i64 1
+  %tmp1 = load i32, i32* %add.ptr, align 4
+  %sexttmp = zext i32 %tmp to i64
+  %sexttmp1 = sext i32 %tmp1 to i64
+  %add = add nsw i64 %sexttmp1, %sexttmp
+  %add1 = add nsw i64 %add, %tmp0
+  ret i64 %add1
+}
+
+; Verify we don't cluster volatile loads.
+; CHECK: ********** MI Scheduling **********
+; CHECK-LABEL: ldr_int_volatile:BB#0
+; CHECK-NOT: Cluster loads
+; CHECK: SU(1):   %vreg{{[0-9]+}}<def> = LDRWui
+; CHECK: SU(2):   %vreg{{[0-9]+}}<def> = LDRWui
+define i32 @ldr_int_volatile(i32* %a) nounwind {
+  %p1 = getelementptr inbounds i32, i32* %a, i32 1
+  %tmp1 = load volatile i32, i32* %p1, align 2
+  %p2 = getelementptr inbounds i32, i32* %a, i32 2
+  %tmp2 = load volatile i32, i32* %p2, align 2
+  %tmp3 = add i32 %tmp1, %tmp2
+  ret i32 %tmp3
+}