vendor/llvm/llvm-r84949

1 files changed, 207 insertions, 0 deletions

diff --git a/test/CodeGen/X86/loop-blocks.ll b/test/CodeGen/X86/loop-blocks.ll
new file mode 100644
index 0000000000000..c0379d115220c
--- /dev/null
+++ b/test/CodeGen/X86/loop-blocks.ll
@@ -0,0 +1,207 @@
+; RUN: llc < %s -march=x86-64 -mtriple=x86_64-unknown-linux-gnu -asm-verbose=false | FileCheck %s
+
+; These tests check for loop branching structure, and that the loop align
+; directive is placed in the expected place.
+
+; CodeGen should insert a branch into the middle of the loop in
+; order to avoid a branch within the loop.
+
+; CHECK: simple:
+;      CHECK:   jmp   .LBB1_1
+; CHECK-NEXT:   align
+; CHECK-NEXT: .LBB1_2:
+; CHECK-NEXT:   call loop_latch
+; CHECK-NEXT: .LBB1_1:
+; CHECK-NEXT:   call loop_header
+
+define void @simple() nounwind {
+entry:
+  br label %loop
+
+loop:
+  call void @loop_header()
+  %t0 = tail call i32 @get()
+  %t1 = icmp slt i32 %t0, 0
+  br i1 %t1, label %done, label %bb
+
+bb:
+  call void @loop_latch()
+  br label %loop
+
+done:
+  call void @exit()
+  ret void
+}
+
+; CodeGen should move block_a to the top of the loop so that it
+; falls through into the loop, avoiding a branch within the loop.
+
+; CHECK: slightly_more_involved:
+;      CHECK:   jmp .LBB2_1
+; CHECK-NEXT:   align
+; CHECK-NEXT: .LBB2_4:
+; CHECK-NEXT:   call bar99
+; CHECK-NEXT: .LBB2_1:
+; CHECK-NEXT:   call body
+
+define void @slightly_more_involved() nounwind {
+entry:
+  br label %loop
+
+loop:
+  call void @body()
+  %t0 = call i32 @get()
+  %t1 = icmp slt i32 %t0, 2
+  br i1 %t1, label %block_a, label %bb
+
+bb:
+  %t2 = call i32 @get()
+  %t3 = icmp slt i32 %t2, 99
+  br i1 %t3, label %exit, label %loop
+
+block_a:
+  call void @bar99()
+  br label %loop
+
+exit:
+  call void @exit()
+  ret void
+}
+
+; Same as slightly_more_involved, but block_a is now a CFG diamond with
+; fallthrough edges which should be preserved.
+
+; CHECK: yet_more_involved:
+;      CHECK:   jmp .LBB3_1
+; CHECK-NEXT:   align
+; CHECK-NEXT: .LBB3_3:
+; CHECK-NEXT:   call bar99
+; CHECK-NEXT:   call get
+; CHECK-NEXT:   cmpl $2999, %eax
+; CHECK-NEXT:   jg .LBB3_5
+; CHECK-NEXT:   call block_a_true_func
+; CHECK-NEXT:   jmp .LBB3_6
+; CHECK-NEXT: .LBB3_5:
+; CHECK-NEXT:   call block_a_false_func
+; CHECK-NEXT: .LBB3_6:
+; CHECK-NEXT:   call block_a_merge_func
+; CHECK-NEXT: .LBB3_1:
+; CHECK-NEXT:   call body
+
+define void @yet_more_involved() nounwind {
+entry:
+  br label %loop
+
+loop:
+  call void @body()
+  %t0 = call i32 @get()
+  %t1 = icmp slt i32 %t0, 2
+  br i1 %t1, label %block_a, label %bb
+
+bb:
+  %t2 = call i32 @get()
+  %t3 = icmp slt i32 %t2, 99
+  br i1 %t3, label %exit, label %loop
+
+block_a:
+  call void @bar99()
+  %z0 = call i32 @get()
+  %z1 = icmp slt i32 %z0, 3000
+  br i1 %z1, label %block_a_true, label %block_a_false
+
+block_a_true:
+  call void @block_a_true_func()
+  br label %block_a_merge
+
+block_a_false:
+  call void @block_a_false_func()
+  br label %block_a_merge
+
+block_a_merge:
+  call void @block_a_merge_func()
+  br label %loop
+
+exit:
+  call void @exit()
+  ret void
+}
+
+; CodeGen should move the CFG islands that are part of the loop but don't
+; conveniently fit anywhere so that they are at least contiguous with the
+; loop.
+
+; CHECK: cfg_islands:
+;      CHECK:   jmp     .LBB4_1
+; CHECK-NEXT:   align
+; CHECK-NEXT: .LBB4_7:
+; CHECK-NEXT:   call    bar100
+; CHECK-NEXT:   jmp     .LBB4_1
+; CHECK-NEXT: .LBB4_8:
+; CHECK-NEXT:   call    bar101
+; CHECK-NEXT:   jmp     .LBB4_1
+; CHECK-NEXT: .LBB4_9:
+; CHECK-NEXT:   call    bar102
+; CHECK-NEXT:   jmp     .LBB4_1
+; CHECK-NEXT: .LBB4_5:
+; CHECK-NEXT:   call    loop_latch
+; CHECK-NEXT: .LBB4_1:
+; CHECK-NEXT:   call    loop_header
+
+define void @cfg_islands() nounwind {
+entry:
+  br label %loop
+
+loop:
+  call void @loop_header()
+  %t0 = call i32 @get()
+  %t1 = icmp slt i32 %t0, 100
+  br i1 %t1, label %block100, label %bb
+
+bb:
+  %t2 = call i32 @get()
+  %t3 = icmp slt i32 %t2, 101
+  br i1 %t3, label %block101, label %bb1
+
+bb1:
+  %t4 = call i32 @get()
+  %t5 = icmp slt i32 %t4, 102
+  br i1 %t5, label %block102, label %bb2
+
+bb2:
+  %t6 = call i32 @get()
+  %t7 = icmp slt i32 %t6, 103
+  br i1 %t7, label %exit, label %bb3
+
+bb3:
+  call void @loop_latch()
+  br label %loop
+
+exit:
+  call void @exit()
+  ret void
+
+block100:
+  call void @bar100()
+  br label %loop
+
+block101:
+  call void @bar101()
+  br label %loop
+
+block102:
+  call void @bar102()
+  br label %loop
+}
+
+declare void @bar99() nounwind
+declare void @bar100() nounwind
+declare void @bar101() nounwind
+declare void @bar102() nounwind
+declare void @body() nounwind
+declare void @exit() nounwind
+declare void @loop_header() nounwind
+declare void @loop_latch() nounwind
+declare i32 @get() nounwind
+declare void @block_a_true_func() nounwind
+declare void @block_a_false_func() nounwind
+declare void @block_a_merge_func() nounwind