vendor/llvm/llvm-trunk-r303571

3 files changed, 140 insertions, 2 deletions

diff --git a/test/Transforms/JumpThreading/assume.ll b/test/Transforms/JumpThreading/assume.ll
index 53010b71c728..3a039676e172 100644
--- a/test/Transforms/JumpThreading/assume.ll
+++ b/test/Transforms/JumpThreading/assume.ll
@@ -56,6 +56,50 @@ return:                                           ; preds = %entry, %if.then
   ret i32 %retval.0
 }
 
+@g = external global i32
+
+; Check that we do prove a fact using an assume within the block.
+; FIXME: We can fold the assume based on the semantics of assume.
+; CHECK-LABEL: @can_fold_assume
+; CHECK: %notnull = icmp ne i32* %array, null
+; CHECK-NEXT: call void @llvm.assume(i1 %notnull)
+; CHECK-NEXT: ret void
+define void @can_fold_assume(i32* %array) {
+  %notnull = icmp ne i32* %array, null
+  call void @llvm.assume(i1 %notnull)
+  br i1 %notnull, label %normal, label %error
+
+normal:
+  ret void
+
+error:
+  store atomic i32 0, i32* @g unordered, align 4
+  ret void
+}
+
+declare void @f(i1)
+declare void @exit()
+; We can fold the assume but not the uses before the assume.
+define void @dont_fold_incorrectly(i32* %array) {
+; CHECK-LABEL:@dont_fold_incorrectly
+; CHECK: @f(i1 %notnull)
+; CHECK-NEXT: exit()
+; CHECK-NEXT: assume(i1 %notnull)
+; CHECK-NEXT: ret void
+  %notnull = icmp ne i32* %array, null
+  call void @f(i1 %notnull)
+  call void @exit()
+  call void @llvm.assume(i1 %notnull)
+  br i1 %notnull, label %normal, label %error
+
+normal:
+  ret void
+
+error:
+  store atomic i32 0, i32* @g unordered, align 4
+  ret void
+}
+
 ; Function Attrs: nounwind
 declare void @llvm.assume(i1) #1
 
diff --git a/test/Transforms/JumpThreading/fold-not-thread.ll b/test/Transforms/JumpThreading/fold-not-thread.ll
index 06ddc10e02b6..f05169b31bc8 100644
--- a/test/Transforms/JumpThreading/fold-not-thread.ll
+++ b/test/Transforms/JumpThreading/fold-not-thread.ll
@@ -133,10 +133,10 @@ L3:
   ret void
 }
 
-; Make sure we can do the RAUW for %add...
+; FIXME: Make sure we can do the RAUW for %add...
 ;
 ; CHECK-LABEL: @rauw_if_possible(
-; CHECK: call void @f4(i32 96) 
+; CHECK: call void @f4(i32 %add)
 define void @rauw_if_possible(i32 %value) nounwind {
 entry:
   %cmp = icmp eq i32 %value, 32
diff --git a/test/Transforms/JumpThreading/guards.ll b/test/Transforms/JumpThreading/guards.ll
index eac2b5dcd85f..c5f72b113efc 100644
--- a/test/Transforms/JumpThreading/guards.ll
+++ b/test/Transforms/JumpThreading/guards.ll
@@ -181,3 +181,97 @@ Exit:
 ; CHECK-NEXT:    ret void
   ret void
 }
+
+declare void @never_called()
+
+; Assume the guard is always taken and we deoptimize, so we never reach the
+; branch below that guard. We should *never* change the behaviour of a guard from
+; `must deoptimize` to `may deoptimize`, since this affects the program
+; semantics.
+define void @dont_fold_guard(i8* %addr, i32 %i, i32 %length) {
+; CHECK-LABEL: dont_fold_guard
+; CHECK: experimental.guard(i1 %wide.chk)
+
+entry:
+  br label %BBPred
+
+BBPred:
+ %cond = icmp eq i8* %addr, null
+ br i1 %cond, label %zero, label %not_zero
+
+zero:
+  unreachable
+
+not_zero:
+  %c1 = icmp ult i32 %i, %length
+  %c2 = icmp eq i32 %i, 0
+  %wide.chk = and i1 %c1, %c2
+  call void(i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
+  br i1 %c2, label %unreachedBB2, label %unreachedBB1
+
+unreachedBB2:
+  call void @never_called()
+  ret void
+
+unreachedBB1:
+  ret void
+}
+
+
+; same as dont_fold_guard1 but condition %cmp is not an instruction.
+; We cannot fold the guard under any circumstance.
+; FIXME: We can merge unreachableBB2 into not_zero.
+define void @dont_fold_guard2(i8* %addr, i1 %cmp, i32 %i, i32 %length) {
+; CHECK-LABEL: dont_fold_guard2
+; CHECK: guard(i1 %cmp)
+
+entry:
+  br label %BBPred
+
+BBPred:
+ %cond = icmp eq i8* %addr, null
+ br i1 %cond, label %zero, label %not_zero
+
+zero:
+  unreachable
+
+not_zero:
+  call void(i1, ...) @llvm.experimental.guard(i1 %cmp) [ "deopt"() ]
+  br i1 %cmp, label %unreachedBB2, label %unreachedBB1
+
+unreachedBB2:
+  call void @never_called()
+  ret void
+
+unreachedBB1:
+  ret void
+}
+
+; Same as dont_fold_guard1 but use switch instead of branch.
+; triggers source code `ProcessThreadableEdges`.
+declare void @f(i1)
+define void @dont_fold_guard3(i1 %cmp1, i32 %i) nounwind {
+; CHECK-LABEL: dont_fold_guard3 
+; CHECK-LABEL: L2:
+; CHECK-NEXT: %cmp = icmp eq i32 %i, 0 
+; CHECK-NEXT: guard(i1 %cmp)
+; CHECK-NEXT: @f(i1 %cmp)
+; CHECK-NEXT: ret void
+entry:
+  br i1 %cmp1, label %L0, label %L3 
+L0:
+  %cmp = icmp eq i32 %i, 0
+  call void(i1, ...) @llvm.experimental.guard(i1 %cmp) [ "deopt"() ]
+  switch i1 %cmp, label %L3 [
+    i1 false, label %L1
+    i1 true, label %L2
+    ]
+
+L1:
+  ret void
+L2:
+  call void @f(i1 %cmp)
+  ret void
+L3:
+  ret void
+}