ARM: implement some simple f64 materializations.

Previously we used a const-pool load for virtually all 64-bit floating values.
Actually, we can get quite a few common values (including 0.0, 1.0) via "vmov"
instructions of one stripe or another.

llvm-svn: 188773

2 files changed, 70 insertions, 3 deletions

diff --git a/llvm/test/CodeGen/ARM/constantfp.ll b/llvm/test/CodeGen/ARM/constantfp.ll
new file mode 100644
index 00000000000..974bdd729ef
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/constantfp.ll
@@ -0,0 +1,68 @@
+; RUN: llc -mtriple=armv7 -mattr=+neon -mcpu=swift %s -o - | FileCheck %s
+; RUN: llc -mtriple=armv7 -mattr=+neon -mcpu=cortex-a8 %s -o - | FileCheck --check-prefix=CHECK-NONEONFP %s
+; RUN: llc -mtriple=armv7 -mattr=-neon -mcpu=cortex-a8 %s -o - | FileCheck --check-prefix=CHECK-NONEON %s
+
+define arm_aapcs_vfpcc float @test_vmov_f32() {
+; CHECK-LABEL: test_vmov_f32:
+; CHECK: vmov.f32 d0, #1.0
+
+; CHECK-NONEONFP: vmov.f32 s0, #1.0
+  ret float 1.0
+}
+
+define arm_aapcs_vfpcc float @test_vmov_imm() {
+; CHECK-LABEL: test_vmov_imm:
+; CHECK: vmov.i32 d0, #0
+
+; CHECK-NONEON-LABEL: test_vmov_imm:
+; CHECK_NONEON: vldr s0, {{.?LCPI[0-9]+_[0-9]+}}
+  ret float 0.0
+}
+
+define arm_aapcs_vfpcc float @test_vmvn_imm() {
+; CHECK-LABEL: test_vmvn_imm:
+; CHECK: vmvn.i32 d0, #0xb0000000
+
+; CHECK-NONEON-LABEL: test_vmvn_imm:
+; CHECK_NONEON: vldr s0, {{.?LCPI[0-9]+_[0-9]+}}
+  ret float 8589934080.0
+}
+
+define arm_aapcs_vfpcc double @test_vmov_f64() {
+; CHECK-LABEL: test_vmov_f64:
+; CHECK: vmov.f64 d0, #1.0
+
+; CHECK-NONEON-LABEL: test_vmov_f64:
+; CHECK_NONEON: vmov.f64 d0, #1.0
+
+  ret double 1.0
+}
+
+define arm_aapcs_vfpcc double @test_vmov_double_imm() {
+; CHECK-LABEL: test_vmov_double_imm:
+; CHECK: vmov.i32 d0, #0
+
+; CHECK-NONEON-LABEL: test_vmov_double_imm:
+; CHECK_NONEON: vldr d0, {{.?LCPI[0-9]+_[0-9]+}}
+  ret double 0.0
+}
+
+define arm_aapcs_vfpcc double @test_vmvn_double_imm() {
+; CHECK-LABEL: test_vmvn_double_imm:
+; CHECK: vmvn.i32 d0, #0xb0000000
+
+; CHECK-NONEON-LABEL: test_vmvn_double_imm:
+; CHECK_NONEON: vldr d0, {{.?LCPI[0-9]+_[0-9]+}}
+  ret double 0x4fffffff4fffffff
+}
+
+; Make sure we don't ignore the high half of 64-bit values when deciding whether
+; a vmov/vmvn is possible.
+define arm_aapcs_vfpcc double @test_notvmvn_double_imm() {
+; CHECK-LABEL: test_notvmvn_double_imm:
+; CHECK: vldr d0, {{.?LCPI[0-9]+_[0-9]+}}
+
+; CHECK-NONEON-LABEL: test_notvmvn_double_imm:
+; CHECK_NONEON: vldr d0, {{.?LCPI[0-9]+_[0-9]+}}
+  ret double 0x4fffffffffffffff
+}
diff --git a/llvm/test/CodeGen/ARM/reg_sequence.ll b/llvm/test/CodeGen/ARM/reg_sequence.ll
index 3fe2bb8e382..25484f48485 100644
--- a/llvm/test/CodeGen/ARM/reg_sequence.ll
+++ b/llvm/test/CodeGen/ARM/reg_sequence.ll
@@ -239,10 +239,9 @@ bb14:                                             ; preds = %bb6
 ; PR7157
 define arm_aapcs_vfpcc float @t9(%0* nocapture, %3* nocapture) nounwind {
 ; CHECK-LABEL:        t9:
-; CHECK:        vldr
-; CHECK-NOT:    vmov d{{.*}}, d16
-; CHECK:        vmov.i32 d17
+; CHECK: vmov.i32 d16, #0x0
 ; CHECK-NEXT:   vst1.64 {d16, d17}, [r0:128]
+; CHECK-NEXT:   vorr d17, d16, d16
 ; CHECK-NEXT:   vst1.64 {d16, d17}, [r0:128]
   %3 = bitcast double 0.000000e+00 to <2 x float> ; <<2 x float>> [#uses=2]
   %4 = shufflevector <2 x float> %3, <2 x float> undef, <4 x i32> <i32 0, i32 1, i32 2, i32 3> ; <<4 x float>> [#uses=1]