[LoopVersioning] Require loop-simplify form for loop versioning.

Summary:
Requiring loop-simplify form for loop versioning ensures that the
runtime check block always dominates the exit block.
    
This patch closes #30958 (https://llvm.org/bugs/show_bug.cgi?id=30958).

Reviewers: silviu.baranga, hfinkel, anemet, ashutosh.nema

Subscribers: ashutosh.nema, mzolotukhin, efriedma, hfinkel, llvm-commits

Differential Revision: https://reviews.llvm.org/D27469

llvm-svn: 290116

5 files changed, 53 insertions, 10 deletions

diff --git a/llvm/test/Transforms/LoopDistribute/diagnostics-with-hotness.ll b/llvm/test/Transforms/LoopDistribute/diagnostics-with-hotness.ll
index be44fe2b44c..63f63997e76 100644
--- a/llvm/test/Transforms/LoopDistribute/diagnostics-with-hotness.ll
+++ b/llvm/test/Transforms/LoopDistribute/diagnostics-with-hotness.ll
@@ -1,14 +1,14 @@
-; RUN: opt -loop-distribute -S -pass-remarks-missed=loop-distribute \
+; RUN: opt -loop-simplify -loop-distribute -S -pass-remarks-missed=loop-distribute \
 ; RUN:     -pass-remarks-analysis=loop-distribute \
 ; RUN:     -pass-remarks-with-hotness < %s 2>&1 | FileCheck %s --check-prefix=HOTNESS
-; RUN: opt -loop-distribute -S -pass-remarks-missed=loop-distribute \
+; RUN: opt -loop-simplify -loop-distribute -S -pass-remarks-missed=loop-distribute \
 ; RUN:     -pass-remarks-analysis=loop-distribute \
 ; RUN:                                < %s 2>&1 | FileCheck %s --check-prefix=NO_HOTNESS
 
-; RUN: opt -passes='require<aa>,loop-distribute' -S -pass-remarks-missed=loop-distribute \
+; RUN: opt -passes='loop-simplify,require<aa>,loop-distribute' -S -pass-remarks-missed=loop-distribute \
 ; RUN:     -pass-remarks-analysis=loop-distribute \
 ; RUN:     -pass-remarks-with-hotness < %s 2>&1 | FileCheck %s --check-prefix=HOTNESS
-; RUN: opt -passes='require<aa>,loop-distribute' -S -pass-remarks-missed=loop-distribute \
+; RUN: opt -passes='loop-simplify,require<aa>,loop-distribute' -S -pass-remarks-missed=loop-distribute \
 ; RUN:     -pass-remarks-analysis=loop-distribute \
 ; RUN:                                < %s 2>&1 | FileCheck %s --check-prefix=NO_HOTNESS
 
diff --git a/llvm/test/Transforms/LoopDistribute/diagnostics.ll b/llvm/test/Transforms/LoopDistribute/diagnostics.ll
index 9c0d915dfaf..ada24364875 100644
--- a/llvm/test/Transforms/LoopDistribute/diagnostics.ll
+++ b/llvm/test/Transforms/LoopDistribute/diagnostics.ll
@@ -1,10 +1,13 @@
-; RUN: opt -loop-distribute -S < %s 2>&1 \
+; RUN: opt -loop-simplify -loop-distribute -S < %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefix=ALWAYS --check-prefix=NO_REMARKS
-; RUN: opt -loop-distribute -S -pass-remarks-missed=loop-distribute < %s 2>&1 \
+; RUN: opt -loop-simplify -loop-distribute -S \
+; RUN:     -pass-remarks-missed=loop-distribute < %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefix=ALWAYS --check-prefix=MISSED_REMARKS
-; RUN: opt -loop-distribute -S -pass-remarks-analysis=loop-distribute < %s 2>&1 \
+; RUN: opt -loop-simplify -loop-distribute -S \
+; RUN:     -pass-remarks-analysis=loop-distribute < %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefix=ALWAYS --check-prefix=ANALYSIS_REMARKS
-; RUN: opt -loop-distribute -S -pass-remarks=loop-distribute < %s 2>&1 \
+; RUN: opt -loop-simplify -loop-distribute -S \
+; RUN:     -pass-remarks=loop-distribute < %s 2>&1 \
 ; RUN:     | FileCheck %s --check-prefix=ALWAYS --check-prefix=REMARKS
 
 ; This is the input program:
diff --git a/llvm/test/Transforms/LoopVectorize/diag-with-hotness-info.ll b/llvm/test/Transforms/LoopVectorize/diag-with-hotness-info.ll
index 04bd5df2465..43bf9ceb217 100644
--- a/llvm/test/Transforms/LoopVectorize/diag-with-hotness-info.ll
+++ b/llvm/test/Transforms/LoopVectorize/diag-with-hotness-info.ll
@@ -10,7 +10,8 @@
 ; RUN:     -pass-remarks-with-hotness < %s 2>&1 | \
 ; RUN:     FileCheck -check-prefix=HOTNESS -check-prefix=BOTH %s
 
-; RUN: opt -S -passes=loop-vectorize -pass-remarks-missed=loop-vectorize < %s 2>&1 | \
+; RUN: opt -S -passes=loop-vectorize \
+; RUN:     -pass-remarks-missed=loop-vectorize < %s 2>&1 | \
 ; RUN:     FileCheck -check-prefix=NO_HOTNESS -check-prefix=BOTH %s
 
 
diff --git a/llvm/test/Transforms/LoopVersioning/exit-block-dominates-rt-check-block.ll b/llvm/test/Transforms/LoopVersioning/exit-block-dominates-rt-check-block.ll
new file mode 100644
index 00000000000..51bfb28bdb1
--- /dev/null
+++ b/llvm/test/Transforms/LoopVersioning/exit-block-dominates-rt-check-block.ll
@@ -0,0 +1,38 @@
+; This test ensures loop versioning does not produce an invalid dominator tree
+; if the exit block of the loop (bb0) dominates the runtime check block
+; (bb1 will become the runtime check block).
+
+; RUN: opt -loop-distribute -verify-dom-info -S -o - %s > %t
+; RUN: opt -loop-simplify -loop-distribute -verify-dom-info -S -o - %s > %t
+; RUN: FileCheck --check-prefix CHECK-VERSIONING -input-file %t %s
+
+; RUN: opt -loop-versioning -verify-dom-info -S -o - %s > %t
+; RUN: opt -loop-simplify -loop-versioning -verify-dom-info -S -o - %s > %t
+; RUN: FileCheck --check-prefix CHECK-VERSIONING -input-file %t %s
+
+@c1 = external global i16
+
+define void @f(i16 %a) {
+  br label %bb0
+
+bb0:
+  br label %bb1
+
+bb1:
+  %tmp1 = load i16, i16* @c1
+  br label %bb2
+
+bb2:
+  %tmp2 = phi i16 [ %tmp1, %bb1 ], [ %tmp3, %bb2 ]
+  %tmp4 = getelementptr inbounds [1 x i32], [1 x i32]* undef, i32 0, i32 4
+  store i32 1, i32* %tmp4
+  %tmp5 = getelementptr inbounds [1 x i32], [1 x i32]* undef, i32 0, i32 9
+  store i32 0, i32* %tmp5
+  %tmp3 = add i16 %tmp2, 1
+  store i16 %tmp2, i16* @c1
+  %tmp6 = icmp sle i16 %tmp3, 0
+  br i1 %tmp6, label %bb2, label %bb0
+}
+
+; Simple check to make sure loop versioning happened.
+; CHECK-VERSIONING: bb2.lver.check:
diff --git a/llvm/test/Transforms/LoopVersioning/noalias-version-twice.ll b/llvm/test/Transforms/LoopVersioning/noalias-version-twice.ll
index 81ec0c0dc9f..50f3616a061 100644
--- a/llvm/test/Transforms/LoopVersioning/noalias-version-twice.ll
+++ b/llvm/test/Transforms/LoopVersioning/noalias-version-twice.ll
@@ -1,4 +1,5 @@
-; RUN: opt -basicaa -loop-distribute -scoped-noalias -loop-versioning -S < %s | FileCheck %s
+; RUN: opt -basicaa -loop-distribute -loop-simplify -scoped-noalias \
+; RUN:     -loop-versioning -S < %s | FileCheck %s
 
 ; Test the metadata generated when versioning an already versioned loop.  Here
 ; we invoke loop distribution to perform the first round of versioning.  It