GVN-hoist: fix hoistingFromAllPaths for loops (PR29034)

It is invalid to hoist stores or loads if they are not executed on all paths
from the hoisting point to the exit of the function. In the testcase, there are
paths in the loop that do not execute the stores or the loads, and so hoisting
them within the loop is unsafe.

The problem is that the current implementation of hoistingFromAllPaths is
incomplete: it walks all blocks dominated by the hoisting point, and does not
return false when the loop contains a path on which the hoisted ld/st is
not executed.

Differential Revision: https://reviews.llvm.org/D23843

llvm-svn: 279732

2 files changed, 173 insertions, 0 deletions

diff --git a/llvm/test/Transforms/GVNHoist/pr29031.ll b/llvm/test/Transforms/GVNHoist/pr29031.ll
new file mode 100644
index 00000000000..cd518725b8b
--- /dev/null
+++ b/llvm/test/Transforms/GVNHoist/pr29031.ll
@@ -0,0 +1,51 @@
+; RUN: opt -S -gvn-hoist < %s | FileCheck %s
+
+; Check that the stores are not hoisted: it is invalid to hoist stores if they
+; are not executed on all paths. In this testcase, there are paths in the loop
+; that do not execute the stores.
+
+; CHECK-LABEL: define i32 @main
+; CHECK: store
+; CHECK: store
+; CHECK: store
+
+@a = global i32 0, align 4
+
+define i32 @main() {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc5, %entry
+  %0 = load i32, i32* @a, align 4
+  %cmp = icmp slt i32 %0, 1
+  br i1 %cmp, label %for.cond1, label %for.end7
+
+for.cond1:                                        ; preds = %for.cond, %for.inc
+  %1 = load i32, i32* @a, align 4
+  %cmp2 = icmp slt i32 %1, 1
+  br i1 %cmp2, label %for.body3, label %for.inc5
+
+for.body3:                                        ; preds = %for.cond1
+  %tobool = icmp ne i32 %1, 0
+  br i1 %tobool, label %if.then, label %for.inc
+
+if.then:                                          ; preds = %for.body3
+  %inc = add nsw i32 %1, 1
+  store i32 %inc, i32* @a, align 4
+  br label %for.inc
+
+for.inc:                                          ; preds = %for.body3, %if.then
+  %2 = load i32, i32* @a, align 4
+  %inc4 = add nsw i32 %2, 1
+  store i32 %inc4, i32* @a, align 4
+  br label %for.cond1
+
+for.inc5:                                         ; preds = %for.cond1
+  %inc6 = add nsw i32 %1, 1
+  store i32 %inc6, i32* @a, align 4
+  br label %for.cond
+
+for.end7:                                         ; preds = %for.cond
+  ret i32 %0
+}
+
diff --git a/llvm/test/Transforms/GVNHoist/pr29034.ll b/llvm/test/Transforms/GVNHoist/pr29034.ll
new file mode 100644
index 00000000000..5e725ad38c8
--- /dev/null
+++ b/llvm/test/Transforms/GVNHoist/pr29034.ll
@@ -0,0 +1,122 @@
+; RUN: opt -S -gvn-hoist < %s | FileCheck %s
+
+; Check that the stores are not hoisted: it is invalid to hoist stores if they
+; are not executed on all paths. In this testcase, there are paths in the loop
+; that do not execute the stores.
+
+; CHECK-LABEL: define void @music_task
+; CHECK: store
+; CHECK: store
+; CHECK: store
+
+
+%struct._MUSIC_OP_API_ = type { %struct._FILE_OPERATE_*, %struct.__MUSIC_API* }
+%struct._FILE_OPERATE_ = type { %struct._FILE_OPERATE_INIT_*, %struct._lg_dev_info_* }
+%struct._FILE_OPERATE_INIT_ = type { i32, i32, i32, i32, i32*, i8*, i32 }
+%struct._lg_dev_info_ = type { %struct.os_event, i32, i32, %struct._lg_dev_hdl_*, i8, i8, i8, i8, i8 }
+%struct.os_event = type { i8, i32, i8*, %union.anon }
+%union.anon = type { %struct.event_cnt }
+%struct.event_cnt = type { i16 }
+%struct._lg_dev_hdl_ = type { i8*, i8*, i8*, i8*, i8* }
+%struct.__MUSIC_API = type <{ i8*, i8*, i32, %struct._DEC_API, %struct._DEC_API_IO*, %struct._FS_BRK_POINT* }>
+%struct._DEC_API = type { %struct._DEC_PHY*, i8*, i8*, i8* (i8*)*, i32* (i8*)*, i8*, %struct._AAC_DEFAULT_SETTING, i32, i32, i8*, %struct.decoder_inf*, i32, i8, i8*, i8, i8* }
+%struct._DEC_PHY = type { i8*, %struct.__audio_decoder_ops*, i8*, %struct.if_decoder_io, %struct.if_dec_file*, i8*, i32 (i8*)*, i32, i8, %struct.__FF_FR }
+%struct.__audio_decoder_ops = type { i8*, i32 (i8*, %struct.if_decoder_io*, i8*)*, i32 (i8*)*, i32 (i8*, i32)*, %struct.decoder_inf* (i8*)*, i32 (i8*)*, i32 (i8*)*, i32 (...)*, i32 (...)*, i32 (...)*, void (i8*, i32)*, void (i8*, i32, i8*, i32)*, i32 (i8*, i32, i8*)* }
+%struct.if_decoder_io = type { i8*, i32 (i8*, i32, i8*, i32, i8)*, i32 (i8*, i32, i8*)*, void (i8*, i8*, i32)*, i32 (i8*)*, i32 (i8*, i32, i32)* }
+%struct.if_dec_file = type { i32 (i8*, i8*, i32)*, i32 (i8*, i32, i32)* }
+%struct.__FF_FR = type { i32, i32, i8, i8, i8 }
+%struct._AAC_DEFAULT_SETTING = type { i32, i32, i32 }
+%struct.decoder_inf = type { i16, i16, i32, i32 }
+%struct._DEC_API_IO = type { i8*, i8*, i16 (i8*, i8*, i16)*, i32 (i8*, i8, i32)*, i32 (%struct.decoder_inf*, i32)*, %struct.__OP_IO, i32, i32 }
+%struct.__OP_IO = type { i8*, i8* (i8*, i8*, i32)* }
+%struct._FS_BRK_POINT = type { %struct._FS_BRK_INFO, i32, i32 }
+%struct._FS_BRK_INFO = type { i32, i32, [8 x i8], i8, i8, i16 }
+
+@.str = external hidden unnamed_addr constant [10 x i8], align 1
+
+define void @music_task(i8* nocapture readnone %p) local_unnamed_addr {
+entry:
+  %mapi = alloca %struct._MUSIC_OP_API_*, align 8
+  %0 = bitcast %struct._MUSIC_OP_API_** %mapi to i8*
+  call void @llvm.lifetime.start(i64 8, i8* %0)
+  store %struct._MUSIC_OP_API_* null, %struct._MUSIC_OP_API_** %mapi, align 8, !tbaa !1
+  %call = call i32 @music_decoder_init(%struct._MUSIC_OP_API_** nonnull %mapi)
+  br label %while.cond
+
+while.cond.loopexit:                              ; preds = %while.cond2
+  br label %while.cond
+
+while.cond:                                       ; preds = %while.cond.loopexit, %entry
+  %1 = load %struct._MUSIC_OP_API_*, %struct._MUSIC_OP_API_** %mapi, align 8, !tbaa !1
+  %dop_api = getelementptr inbounds %struct._MUSIC_OP_API_, %struct._MUSIC_OP_API_* %1, i64 0, i32 1
+  %2 = load %struct.__MUSIC_API*, %struct.__MUSIC_API** %dop_api, align 8, !tbaa !5
+  %file_num = getelementptr inbounds %struct.__MUSIC_API, %struct.__MUSIC_API* %2, i64 0, i32 2
+  %3 = bitcast i32* %file_num to i8*
+  %call1 = call i32 @music_play_api(%struct._MUSIC_OP_API_* %1, i32 33, i32 0, i32 28, i8* %3)
+  br label %while.cond2
+
+while.cond2:                                      ; preds = %while.cond2.backedge, %while.cond
+  %err.0 = phi i32 [ %call1, %while.cond ], [ %err.0.be, %while.cond2.backedge ]
+  switch i32 %err.0, label %sw.default [
+    i32 0, label %while.cond.loopexit
+    i32 35, label %sw.bb
+    i32 11, label %sw.bb7
+    i32 12, label %sw.bb13
+  ]
+
+sw.bb:                                            ; preds = %while.cond2
+  %4 = load %struct._MUSIC_OP_API_*, %struct._MUSIC_OP_API_** %mapi, align 8, !tbaa !1
+  %dop_api4 = getelementptr inbounds %struct._MUSIC_OP_API_, %struct._MUSIC_OP_API_* %4, i64 0, i32 1
+  %5 = load %struct.__MUSIC_API*, %struct.__MUSIC_API** %dop_api4, align 8, !tbaa !5
+  %file_num5 = getelementptr inbounds %struct.__MUSIC_API, %struct.__MUSIC_API* %5, i64 0, i32 2
+  %6 = load i32, i32* %file_num5, align 1, !tbaa !7
+  %call6 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([10 x i8], [10 x i8]* @.str, i64 0, i64 0), i32 %6)
+  br label %while.cond2.backedge
+
+sw.bb7:                                           ; preds = %while.cond2
+  %7 = load %struct._MUSIC_OP_API_*, %struct._MUSIC_OP_API_** %mapi, align 8, !tbaa !1
+  %dop_api8 = getelementptr inbounds %struct._MUSIC_OP_API_, %struct._MUSIC_OP_API_* %7, i64 0, i32 1
+  %8 = load %struct.__MUSIC_API*, %struct.__MUSIC_API** %dop_api8, align 8, !tbaa !5
+  %file_num9 = getelementptr inbounds %struct.__MUSIC_API, %struct.__MUSIC_API* %8, i64 0, i32 2
+  store i32 1, i32* %file_num9, align 1, !tbaa !7
+  %9 = bitcast i32* %file_num9 to i8*
+  %call12 = call i32 @music_play_api(%struct._MUSIC_OP_API_* %7, i32 34, i32 0, i32 24, i8* %9)
+  br label %while.cond2.backedge
+
+sw.bb13:                                          ; preds = %while.cond2
+  %10 = load %struct._MUSIC_OP_API_*, %struct._MUSIC_OP_API_** %mapi, align 8, !tbaa !1
+  %dop_api14 = getelementptr inbounds %struct._MUSIC_OP_API_, %struct._MUSIC_OP_API_* %10, i64 0, i32 1
+  %11 = load %struct.__MUSIC_API*, %struct.__MUSIC_API** %dop_api14, align 8, !tbaa !5
+  %file_num15 = getelementptr inbounds %struct.__MUSIC_API, %struct.__MUSIC_API* %11, i64 0, i32 2
+  store i32 1, i32* %file_num15, align 1, !tbaa !7
+  %12 = bitcast i32* %file_num15 to i8*
+  %call18 = call i32 @music_play_api(%struct._MUSIC_OP_API_* %10, i32 35, i32 0, i32 26, i8* %12)
+  br label %while.cond2.backedge
+
+sw.default:                                       ; preds = %while.cond2
+  %13 = load %struct._MUSIC_OP_API_*, %struct._MUSIC_OP_API_** %mapi, align 8, !tbaa !1
+  %call19 = call i32 @music_play_api(%struct._MUSIC_OP_API_* %13, i32 33, i32 0, i32 22, i8* null)
+  br label %while.cond2.backedge
+
+while.cond2.backedge:                             ; preds = %sw.default, %sw.bb13, %sw.bb7, %sw.bb
+  %err.0.be = phi i32 [ %call19, %sw.default ], [ %call18, %sw.bb13 ], [ %call12, %sw.bb7 ], [ 0, %sw.bb ]
+  br label %while.cond2
+}
+
+declare void @llvm.lifetime.start(i64, i8* nocapture)
+declare i32 @music_decoder_init(%struct._MUSIC_OP_API_**)
+declare i32 @music_play_api(%struct._MUSIC_OP_API_*, i32, i32, i32, i8*)
+declare i32 @printf(i8* nocapture readonly, ...)
+
+!0 = !{!"clang version 4.0.0 "}
+!1 = !{!2, !2, i64 0}
+!2 = !{!"any pointer", !3, i64 0}
+!3 = !{!"omnipotent char", !4, i64 0}
+!4 = !{!"Simple C/C++ TBAA"}
+!5 = !{!6, !2, i64 8}
+!6 = !{!"_MUSIC_OP_API_", !2, i64 0, !2, i64 8}
+!7 = !{!8, !9, i64 16}
+!8 = !{!"__MUSIC_API", !2, i64 0, !2, i64 8, !9, i64 16, !10, i64 20, !2, i64 140, !2, i64 148}
+!9 = !{!"int", !3, i64 0}
+!10 = !{!"_DEC_API", !2, i64 0, !2, i64 8, !2, i64 16, !2, i64 24, !2, i64 32, !2, i64 40, !11, i64 48, !9, i64 60, !9, i64 64, !2, i64 72, !2, i64 80, !9, i64 88, !3, i64 92, !2, i64 96, !3, i64 104, !2, i64 112}
+!11 = !{!"_AAC_DEFAULT_SETTING", !9, i64 0, !9, i64 4, !9, i64 8}