[RewriteStatepointsForGC] For some values (like gep's and bitcasts) it's cheaper to clone them after statepoint than to emit proper relocates for them. This change implements this logic. There is alredy similar optimization in CodeGenPrepare, but doing so during RewriteStatepointsForGC allows to capture more opprtunities such as relocates in loops and longer instruction chains.

Differential Revision: http://reviews.llvm.org/D9774

llvm-svn: 237701

1 files changed, 222 insertions, 0 deletions

diff --git a/llvm/test/Transforms/RewriteStatepointsForGC/rematerialize-derived-pointers.ll b/llvm/test/Transforms/RewriteStatepointsForGC/rematerialize-derived-pointers.ll
new file mode 100644
index 00000000000..dc52bd88776
--- /dev/null
+++ b/llvm/test/Transforms/RewriteStatepointsForGC/rematerialize-derived-pointers.ll
@@ -0,0 +1,222 @@
+; RUN: opt %s -rewrite-statepoints-for-gc -S 2>&1 | FileCheck %s
+
+declare void @use_obj16(i16 addrspace(1)*)
+declare void @use_obj32(i32 addrspace(1)*)
+declare void @use_obj64(i64 addrspace(1)*)
+declare void @do_safepoint()
+
+define void @"test_gep_const"(i32 addrspace(1)* %base) gc "statepoint-example" {
+; CHECK-LABEL: test_gep_const
+entry:
+  %ptr = getelementptr i32, i32 addrspace(1)* %base, i32 15
+  ; CHECK: getelementptr i32, i32 addrspace(1)* %base, i32 15
+  %sp = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+  ; CHECK: %base.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(i32 %sp, i32 7, i32 7)
+  ; CHECK: bitcast i8 addrspace(1)* %base.relocated to i32 addrspace(1)*
+  ; CHECK: getelementptr i32, i32 addrspace(1)* %base.relocated.casted, i32 15
+  call void @use_obj32(i32 addrspace(1)* %base)
+  call void @use_obj32(i32 addrspace(1)* %ptr)
+  ret void
+}
+
+define void @"test_gep_idx"(i32 addrspace(1)* %base, i32 %idx) gc "statepoint-example" {
+; CHECK-LABEL: test_gep_idx
+entry:
+  %ptr = getelementptr i32, i32 addrspace(1)* %base, i32 %idx
+  ; CHECK: getelementptr
+  %sp = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+  ; CHECK: %base.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(i32 %sp, i32 7, i32 7)
+  ; CHECK: %base.relocated.casted = bitcast i8 addrspace(1)* %base.relocated to i32 addrspace(1)*
+  ; CHECK: getelementptr i32, i32 addrspace(1)* %base.relocated.casted, i32 %idx
+  call void @use_obj32(i32 addrspace(1)* %base)
+  call void @use_obj32(i32 addrspace(1)* %ptr)
+  ret void
+}
+
+define void @"test_bitcast"(i32 addrspace(1)* %base) gc "statepoint-example" {
+; CHECK-LABEL: test_bitcast
+entry:
+  %ptr = bitcast i32 addrspace(1)* %base to i64 addrspace(1)*
+  ; CHECK: bitcast i32 addrspace(1)* %base to i64 addrspace(1)*
+  %sp = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+  ; CHECK: %base.relocated = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(i32 %sp, i32 7, i32 7)
+  ; CHECK: %base.relocated.casted = bitcast i8 addrspace(1)* %base.relocated to i32 addrspace(1)*
+  ; CHECK: bitcast i32 addrspace(1)* %base.relocated.casted to i64 addrspace(1)*
+  call void @use_obj32(i32 addrspace(1)* %base)
+  call void @use_obj64(i64 addrspace(1)* %ptr)
+  ret void
+}
+
+define void @"test_bitcast_gep"(i32 addrspace(1)* %base) gc "statepoint-example" {
+; CHECK-LABEL: test_bitcast_gep
+entry:
+  %ptr.gep = getelementptr i32, i32 addrspace(1)* %base, i32 15
+  ; CHECK: getelementptr
+  %ptr.cast = bitcast i32 addrspace(1)* %ptr.gep to i64 addrspace(1)*
+  ; CHECK: bitcast
+  %sp = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+  ; CHECK: gc.relocate
+  ; CHECK: bitcast
+  ; CHECK: getelementptr
+  ; CHECK: bitcast
+  call void @use_obj32(i32 addrspace(1)* %base)
+  call void @use_obj64(i64 addrspace(1)* %ptr.cast)
+  ret void
+}
+
+define void @"test_intersecting_chains"(i32 addrspace(1)* %base, i32 %idx) gc "statepoint-example" {
+; CHECK-LABEL: test_intersecting_chains
+entry:
+  %ptr.gep = getelementptr i32, i32 addrspace(1)* %base, i32 15
+  ; CHECK: getelementptr
+  %ptr.cast = bitcast i32 addrspace(1)* %ptr.gep to i64 addrspace(1)*
+  ; CHECK: bitcast
+  %ptr.cast2 = bitcast i32 addrspace(1)* %ptr.gep to i16 addrspace(1)*
+  ; CHECK: bitcast
+  %sp = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+  ; CHECK: getelementptr
+  ; CHECK: bitcast
+  ; CHECK: getelementptr
+  ; CHECK: bitcast
+  call void @use_obj64(i64 addrspace(1)* %ptr.cast)
+  call void @use_obj16(i16 addrspace(1)* %ptr.cast2)
+  ret void
+}
+
+define void @"test_cost_threshold"(i32 addrspace(1)* %base, i32 %idx1, i32 %idx2, i32 %idx3) gc "statepoint-example" {
+; CHECK-LABEL: test_cost_threshold
+entry:
+  %ptr.gep = getelementptr i32, i32 addrspace(1)* %base, i32 15
+  ; CHECK: getelementptr
+  %ptr.gep2 = getelementptr i32, i32 addrspace(1)* %ptr.gep, i32 %idx1
+  ; CHECK: getelementptr
+  %ptr.gep3 = getelementptr i32, i32 addrspace(1)* %ptr.gep2, i32 %idx2
+  ; CHECK: getelementptr
+  %ptr.gep4 = getelementptr i32, i32 addrspace(1)* %ptr.gep3, i32 %idx3
+  ; CHECK: getelementptr
+  %ptr.cast = bitcast i32 addrspace(1)* %ptr.gep4 to i64 addrspace(1)*
+  ; CHECK: bitcast
+  %sp = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+  ; CHECK: gc.relocate
+  ; CHECK: bitcast
+  ; CHECK: gc.relocate
+  ; CHECK: bitcast
+  call void @use_obj64(i64 addrspace(1)* %ptr.cast)
+  ret void
+}
+
+define void @"test_two_derived"(i32 addrspace(1)* %base) gc "statepoint-example" {
+; CHECK-LABEL: test_two_derived
+entry:
+  %ptr = getelementptr i32, i32 addrspace(1)* %base, i32 15
+  %ptr2 = getelementptr i32, i32 addrspace(1)* %base, i32 12
+  ; CHECK: getelementptr
+  ; CHECK: getelementptr
+  %sp = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+  ; CHECK: gc.relocate
+  ; CHECK: bitcast
+  ; CHECK: getelementptr
+  ; CHECK: getelementptr
+  call void @use_obj32(i32 addrspace(1)* %ptr)
+  call void @use_obj32(i32 addrspace(1)* %ptr2)
+  ret void
+}
+
+define void @"test_gep_smallint_array"([3 x i32] addrspace(1)* %base) gc "statepoint-example" {
+; CHECK-LABEL: test_gep_smallint_array
+entry:
+  %ptr = getelementptr [3 x i32], [3 x i32] addrspace(1)* %base, i32 0, i32 2
+  ; CHECK: getelementptr
+  %sp = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+  ; CHECK: gc.relocate
+  ; CHECK: bitcast
+  ; CHECK: getelementptr
+  call void @use_obj32(i32 addrspace(1)* %ptr)
+  ret void
+}
+
+declare i32 @fake_personality_function()
+
+define void @"test_invoke"(i32 addrspace(1)* %base) gc "statepoint-example" {
+; CHECK-LABEL: test_invoke
+entry:
+  %ptr.gep = getelementptr i32, i32 addrspace(1)* %base, i32 15
+  ; CHECK: getelementptr
+  %ptr.cast = bitcast i32 addrspace(1)* %ptr.gep to i64 addrspace(1)*
+  ; CHECK: bitcast
+  %ptr.cast2 = bitcast i32 addrspace(1)* %ptr.gep to i16 addrspace(1)*
+  ; CHECK: bitcast
+  %sp = invoke i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+                to label %normal unwind label %exception
+
+normal:
+  ; CHECK-LABEL: normal:
+  ; CHECK: gc.relocate
+  ; CHECK: bitcast
+  ; CHECK: getelementptr
+  ; CHECK: bitcast
+  ; CHECK: getelementptr
+  ; CHECK: bitcast
+  call void @use_obj64(i64 addrspace(1)* %ptr.cast)
+  call void @use_obj16(i16 addrspace(1)* %ptr.cast2)
+  ret void
+
+exception:
+  ; CHECK-LABEL: exception:
+  %landing_pad4 = landingpad { i8*, i32 } personality i32 ()* @fake_personality_function
+          cleanup
+  ; CHECK: gc.relocate
+  ; CHECK: bitcast
+  ; CHECK: getelementptr
+  ; CHECK: bitcast
+  ; CHECK: getelementptr
+  ; CHECK: bitcast
+  call void @use_obj64(i64 addrspace(1)* %ptr.cast)
+  call void @use_obj16(i16 addrspace(1)* %ptr.cast2)
+  ret void
+}
+
+define void @"test_loop"(i32 addrspace(1)* %base) gc "statepoint-example" {
+; CHECK-LABEL: test_loop
+entry:
+  %ptr.gep = getelementptr i32, i32 addrspace(1)* %base, i32 15
+  ; CHECK: getelementptr
+  br label %loop
+
+loop:
+  ; CHECK: phi i32 addrspace(1)* [ %ptr.gep, %entry ], [ %ptr.gep.remat, %loop ]
+  ; CHECK: phi i32 addrspace(1)* [ %base, %entry ], [ %base.relocated.casted, %loop ]
+  call void @use_obj32(i32 addrspace(1)* %ptr.gep)
+  %sp = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+  ; CHECK: gc.relocate
+  ; CHECK: bitcast
+  ; CHECK: getelementptr
+  br label %loop
+}
+
+define void @"test_too_long"(i32 addrspace(1)* %base) gc "statepoint-example" {
+; CHECK-LABEL: test_too_long
+entry:
+  %ptr.gep   = getelementptr i32, i32 addrspace(1)* %base, i32 15
+  %ptr.gep1  = getelementptr i32, i32 addrspace(1)* %ptr.gep, i32 15
+  %ptr.gep2  = getelementptr i32, i32 addrspace(1)* %ptr.gep1, i32 15
+  %ptr.gep3  = getelementptr i32, i32 addrspace(1)* %ptr.gep2, i32 15
+  %ptr.gep4  = getelementptr i32, i32 addrspace(1)* %ptr.gep3, i32 15
+  %ptr.gep5  = getelementptr i32, i32 addrspace(1)* %ptr.gep4, i32 15
+  %ptr.gep6  = getelementptr i32, i32 addrspace(1)* %ptr.gep5, i32 15
+  %ptr.gep7  = getelementptr i32, i32 addrspace(1)* %ptr.gep6, i32 15
+  %ptr.gep8  = getelementptr i32, i32 addrspace(1)* %ptr.gep7, i32 15
+  %ptr.gep9  = getelementptr i32, i32 addrspace(1)* %ptr.gep8, i32 15
+  %ptr.gep10 = getelementptr i32, i32 addrspace(1)* %ptr.gep9, i32 15
+  %ptr.gep11 = getelementptr i32, i32 addrspace(1)* %ptr.gep10, i32 15
+  %sp = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
+  ; CHECK: gc.relocate
+  ; CHECK: bitcast
+  ; CHECK: gc.relocate
+  ; CHECK: bitcast
+  call void @use_obj32(i32 addrspace(1)* %ptr.gep11)
+  ret void
+}
+
+
+declare i32 @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)