From edb52c626b5340a5a42ed833fc776bc815507283 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo@fhahn.com>
Date: Sun, 3 Jan 2021 20:27:17 +0000
Subject: [PATCH] [LoopUnswitch] Precommit initial partial unswitching test
 cases.

---
 .../LoopUnswitch/partial-unswitch.ll          | 461 ++++++++++++++++++
 1 file changed, 461 insertions(+)
 create mode 100644 llvm/test/Transforms/LoopUnswitch/partial-unswitch.ll

diff --git a/llvm/test/Transforms/LoopUnswitch/partial-unswitch.ll b/llvm/test/Transforms/LoopUnswitch/partial-unswitch.ll
new file mode 100644
index 000000000000..742e35a99b5d
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnswitch/partial-unswitch.ll
@@ -0,0 +1,461 @@
+; RUN: opt -loop-unswitch -verify-dom-info -verify-memoryssa -S %s | FileCheck %s
+
+declare void @clobber()
+
+define i32 @partial_unswitch_true_successor(i32* %ptr, i32 %N) {
+; CHECK-LABEL: @partial_unswitch_true_successor
+; CHECK-LABEL: entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %lv = load i32, i32* %ptr
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %noclobber, label %clobber
+
+noclobber:
+  br label %loop.latch
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret i32 10
+}
+
+define i32 @partial_unswitch_false_successor(i32* %ptr, i32 %N) {
+; CHECK-LABEL: @partial_unswitch_false_successor
+; CHECK-LABEL: entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %lv = load i32, i32* %ptr
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %clobber, label %noclobber
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+noclobber:
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret i32 10
+}
+
+define i32 @partial_unswtich_gep_load_icmp(i32** %ptr, i32 %N) {
+; CHECK-LABEL: @partial_unswtich_gep_load_icmp
+; CHECK-LABEL: entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %gep = getelementptr i32*, i32** %ptr, i32 1
+  %lv.1 = load i32*, i32** %gep
+  %lv = load i32, i32* %lv.1
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %noclobber, label %clobber
+
+noclobber:
+  br label %loop.latch
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret i32 10
+}
+
+define i32 @partial_unswitch_reduction_phi(i32* %ptr, i32 %N) {
+; CHECK-LABEL: @partial_unswitch_reduction_phi
+; CHECK-LABEL: entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %red = phi i32 [ 20, %entry ], [ %red.next, %loop.latch ]
+  %lv = load i32, i32* %ptr
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %clobber, label %noclobber
+
+clobber:
+  call void @clobber()
+  %add.5 = add i32 %red, 5
+  br label %loop.latch
+
+noclobber:
+  %add.10 = add i32 %red, 10
+  br label %loop.latch
+
+loop.latch:
+  %red.next = phi i32 [ %add.5, %clobber ], [ %add.10, %noclobber ]
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  %red.next.lcssa = phi i32 [ %red.next, %loop.latch ]
+  ret i32 %red.next.lcssa
+}
+
+; Partial unswitching is possible, because the store in %noclobber does not
+; alias the load of the condition.
+define i32 @partial_unswitch_true_successor_noclobber(i32* noalias %ptr.1, i32* noalias %ptr.2, i32 %N) {
+; CHECK-LABEL: @partial_unswitch_true_successor
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %lv = load i32, i32* %ptr.1
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %noclobber, label %clobber
+
+noclobber:
+  %gep.1 = getelementptr i32, i32* %ptr.2, i32 %iv
+  store i32 %lv, i32* %gep.1
+  br label %loop.latch
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret i32 10
+}
+
+define void @no_partial_unswitch_phi_cond(i1 %lc, i32 %N) {
+; CHECK-LABEL: @no_partial_unswitch_phi_cond
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %sc = phi i1 [ %lc, %entry ], [ true, %loop.latch ]
+  br i1 %sc, label %clobber, label %noclobber
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+noclobber:
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret void
+}
+
+define void @no_partial_unswitch_clobber_latch(i32* %ptr, i32 %N) {
+; CHECK-LABEL: @no_partial_unswitch_clobber_latch
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %lv = load i32, i32* %ptr
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %noclobber, label %clobber
+
+noclobber:
+  br label %loop.latch
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+loop.latch:
+  call void @clobber()
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret void
+}
+
+define void @no_partial_unswitch_clobber_header(i32* %ptr, i32 %N) {
+; CHECK-LABEL: @no_partial_unswitch_clobber_header
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  call void @clobber()
+  %lv = load i32, i32* %ptr
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %noclobber, label %clobber
+
+noclobber:
+  br label %loop.latch
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret void
+}
+
+define void @no_partial_unswitch_clobber_both(i32* %ptr, i32 %N) {
+; CHECK-LABEL: @no_partial_unswitch_clobber_both
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %lv = load i32, i32* %ptr
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %noclobber, label %clobber
+
+noclobber:
+  call void @clobber()
+  br label %loop.latch
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret void
+}
+
+define i32 @no_partial_unswitch_true_successor_storeclobber(i32* %ptr.1, i32* %ptr.2, i32 %N) {
+; CHECK-LABEL: @no_partial_unswitch_true_successor_storeclobber
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %lv = load i32, i32* %ptr.1
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %noclobber, label %clobber
+
+noclobber:
+  %gep.1 = getelementptr i32, i32* %ptr.2, i32 %iv
+  store i32 %lv, i32* %gep.1
+  br label %loop.latch
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret i32 10
+}
+
+; Check that MemorySSA updating can deal with a clobbering access of a
+; duplicated load being a MemoryPHI outside the loop.
+define void @partial_unswitch_memssa_update(i32* noalias %ptr, i1 %c) {
+; CHECK-LABEL: @partial_unswitch_memssa_update(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 %c, label %loop.ph, label %outside.clobber
+;
+entry:
+  br i1 %c, label %loop.ph, label %outside.clobber
+
+outside.clobber:
+  call void @clobber()
+  br label %loop.ph
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %lv = load i32, i32* %ptr, align 4
+  %hc = icmp eq i32 %lv, 0
+  br i1 %hc, label %if, label %then
+
+if:
+  br label %loop.latch
+
+then:
+  br label %loop.latch
+
+loop.latch:
+  br i1 true, label %loop.header, label %exit
+
+exit:
+  ret void
+}
+
+; Make sure the duplicated instructions are moved to a preheader that always
+; executes when the loop body also executes. Do not check the unswitched code,
+; because it is already checked in the @partial_unswitch_true_successor test
+; case.
+define i32 @partial_unswitch_true_successor_preheader_insertion(i32* %ptr, i32 %N) {
+; CHECK-LABEL: @partial_unswitch_true_successor_preheader_insertion(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    %ec = icmp ne i32* %ptr, null
+; CHECK-NEXT:    br i1 %ec, label %loop.ph, label %exit
+;
+entry:
+  %ec = icmp ne i32* %ptr, null
+  br i1 %ec, label %loop.ph, label %exit
+
+loop.ph:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %loop.ph ], [ %iv.next, %loop.latch ]
+  %lv = load i32, i32* %ptr
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %noclobber, label %clobber
+
+noclobber:
+  br label %loop.latch
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret i32 10
+}
+
+; Make sure the duplicated instructions are hoisted just before the branch of
+; the preheader. Do not check the unswitched code, because it is already checked
+; in the @partial_unswitch_true_successor test case
+define i32 @partial_unswitch_true_successor_insert_point(i32* %ptr, i32 %N) {
+; CHECK-LABEL: @partial_unswitch_true_successor_insert_point(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    call void @clobber()
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  call void @clobber()
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %lv = load i32, i32* %ptr
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %noclobber, label %clobber
+
+noclobber:
+  br label %loop.latch
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret i32 10
+}
+
+; Make sure invariant instructions in the loop are also hoisted to the preheader.
+; Do not check the unswitched code, because it is already checked in the
+; @partial_unswitch_true_successor test case
+define i32 @partial_unswitch_true_successor_hoist_invariant(i32* %ptr, i32 %N) {
+; CHECK-LABEL: @partial_unswitch_true_successor_hoist_invariant(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label %loop.header
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %gep = getelementptr i32, i32* %ptr, i64 1
+  %lv = load i32, i32* %gep
+  %sc = icmp eq i32 %lv, 100
+  br i1 %sc, label %noclobber, label %clobber
+
+noclobber:
+  br label %loop.latch
+
+clobber:
+  call void @clobber()
+  br label %loop.latch
+
+loop.latch:
+  %c = icmp ult i32 %iv, %N
+  %iv.next = add i32 %iv, 1
+  br i1 %c, label %loop.header, label %exit
+
+exit:
+  ret i32 10
+}