Vendor import of llvm trunk r290819:vendor/llvm/llvm-trunk-r290819

https://llvm.org/svn/llvm-project/llvm/trunk@290819

1 files changed, 190 insertions, 0 deletions

diff --git a/test/CodeGen/X86/tail-dup-merge-loop-headers.ll b/test/CodeGen/X86/tail-dup-merge-loop-headers.ll
new file mode 100644
index 000000000000..197fd72586a5
--- /dev/null
+++ b/test/CodeGen/X86/tail-dup-merge-loop-headers.ll
@@ -0,0 +1,190 @@
+; RUN: llc -O2 -o - %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: nounwind uwtable
+; CHECK-LABEL: tail_dup_merge_loops
+; CHECK: # %entry
+; CHECK-NOT: # %{{[a-zA-Z_]+}}
+; CHECK: # %inner_loop_exit
+; CHECK-NOT: # %{{[a-zA-Z_]+}}
+; CHECK: # %inner_loop_latch
+; CHECK-NOT: # %{{[a-zA-Z_]+}}
+; CHECK: # %inner_loop_test
+; CHECK-NOT: # %{{[a-zA-Z_]+}}
+; CHECK: # %exit
+define void @tail_dup_merge_loops(i32 %a, i8* %b, i8* %c) local_unnamed_addr #0 {
+entry:
+  %notlhs674.i = icmp eq i32 %a, 0
+  br label %outer_loop_top
+
+outer_loop_top:                         ; preds = %inner_loop_exit, %entry
+  %dst.0.ph.i = phi i8* [ %b, %entry ], [ %scevgep679.i, %inner_loop_exit ]
+  br i1 %notlhs674.i, label %exit, label %inner_loop_preheader
+
+inner_loop_preheader:                           ; preds = %outer_loop_top
+  br label %inner_loop_top
+
+inner_loop_top:                                     ; preds = %inner_loop_latch, %inner_loop_preheader
+  %dst.0.i = phi i8* [ %inc, %inner_loop_latch ], [ %dst.0.ph.i, %inner_loop_preheader ]
+  %var = load i8, i8* %dst.0.i
+  %tobool1.i = icmp slt i8 %var, 0
+  br label %inner_loop_test
+
+inner_loop_test:                                       ; preds = %inner_loop_top
+  br i1 %tobool1.i, label %inner_loop_exit, label %inner_loop_latch
+
+inner_loop_exit:                       ; preds = %inner_loop_test
+  %scevgep.i = getelementptr i8, i8* %dst.0.i, i64 1
+  %scevgep679.i = getelementptr i8, i8* %scevgep.i, i64 0
+  br label %outer_loop_top
+
+inner_loop_latch:                                ; preds = %inner_loop_test
+  %cmp75.i = icmp ult i8* %dst.0.i, %c
+  %inc = getelementptr i8, i8* %dst.0.i, i64 2
+  br label %inner_loop_top
+
+exit:                              ; preds = %outer_loop_top
+  ret void
+}
+
+@.str.6 = external unnamed_addr constant [23 x i8], align 1
+
+; There is an erroneus check in LoopBase::addBasicBlockToLoop(), where it
+; assumes that the header block for a loop is unique.
+; For most of compilation this assumption is true, but during layout we allow
+; this assumption to be violated. The following code will trigger the bug:
+
+; The loops in question is eventually headed by the block shared_loop_header
+;
+; During layout The block labeled outer_loop_header gets tail-duplicated into
+; outer_loop_latch, and into shared_preheader, and then removed. This leaves
+; shared_loop_header as the header of both loops. The end result
+; is that there are 2 valid loops, and that they share a header. If we re-ran
+; the loop analysis, it would classify this as a single loop.
+; So far this is fine as far as layout is concerned.
+; After layout we tail merge blocks merge_other and merge_predecessor_split.
+; We do this even though they share only a single instruction, because
+; merge_predecessor_split falls through to their shared successor:
+; outer_loop_latch.
+; The rest of the blocks in the function are noise unfortunately. Bugpoint
+; couldn't shrink the test any further.
+
+; CHECK-LABEL: loop_shared_header
+; CHECK: # %entry
+; CHECK: # %shared_preheader
+; CHECK: # %shared_loop_header
+; CHECK: # %inner_loop_body
+; CHECK: # %outer_loop_latch
+; CHECK: # %merge_predecessor_split
+; CHECK: # %outer_loop_latch
+; CHECK: # %cleanup
+define i32 @loop_shared_header(i8* %exe, i32 %exesz, i32 %headsize, i32 %min, i32 %wwprva, i32 %e_lfanew, i8* readonly %wwp, i32 %wwpsz, i16 zeroext %sects) local_unnamed_addr #0 {
+entry:
+  %0 = load i32, i32* undef, align 4
+  %mul = shl nsw i32 %0, 2
+  br i1 undef, label %if.end19, label %cleanup
+
+if.end19:                                         ; preds = %entry
+  %conv = zext i32 %mul to i64
+  %call = tail call i8* @cli_calloc(i64 %conv, i64 1)
+  %1 = icmp eq i32 %exesz, 0
+  %notrhs = icmp eq i32 %0, 0
+  %or.cond117.not = or i1 %1, %notrhs
+  %or.cond202 = or i1 %or.cond117.not, undef
+  %cmp35 = icmp ult i8* undef, %exe
+  %or.cond203 = or i1 %or.cond202, %cmp35
+  br i1 %or.cond203, label %cleanup, label %if.end50
+
+if.end50:                                         ; preds = %if.end19
+  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull %call, i8* undef, i64 %conv, i32 1, i1 false)
+  %cmp1.i.i = icmp ugt i32 %mul, 3
+  br i1 %cmp1.i.i, label %shared_preheader, label %wunpsect.exit.thread.loopexit391
+
+shared_preheader:                                 ; preds = %if.end50
+  br label %outer_loop_header
+
+outer_loop_header:                                ; preds = %outer_loop_latch, %shared_preheader
+  %bits.1.i = phi i8 [ 32, %shared_preheader ], [ %bits.43.i, %outer_loop_latch ]
+  %dst.0.ph.i = phi i8* [ undef, %shared_preheader ], [ %scevgep679.i, %outer_loop_latch ]
+  %2 = icmp eq i32 undef, 0
+  br i1 %2, label %while.cond.us1412.i, label %shared_loop_header
+
+while.cond.us1412.i:                              ; preds = %outer_loop_header
+  %.pre.i = add i8 %bits.1.i, -1
+  %tobool2.us1420.i = icmp eq i8 %.pre.i, 0
+  %or.cond.us1421.i = or i1 undef, %tobool2.us1420.i
+  br i1 %or.cond.us1421.i, label %if.end41.us1436.i, label %cleanup
+
+if.end41.us1436.i:                                ; preds = %while.cond.us1412.i
+  unreachable
+
+shared_loop_header:                               ; preds = %dup_early2, %dup_early1
+  %dst.0.i = phi i8* [ undef, %inner_loop_body ], [ %dst.0.ph.i, %outer_loop_header ], [ undef, %dead_block ]
+  %cmp3.i1172.i = icmp ult i8* undef, %call
+  br i1 %cmp3.i1172.i, label %wunpsect.exit.thread.loopexit389, label %inner_loop_body
+
+inner_loop_body:                                  ; preds = %shared_loop_header
+  %3 = icmp slt i32 undef, 0
+  br i1 %3, label %if.end96.i, label %shared_loop_header
+
+dead_block:                                       ; preds = %inner_loop_body
+  %cmp75.i = icmp ult i8* %dst.0.i, undef
+  br label %shared_loop_header
+
+if.end96.i:                                       ; preds = %inner_loop_body
+  %cmp97.i = icmp ugt i32 undef, 2
+  br i1 %cmp97.i, label %if.then99.i, label %if.end287.i
+
+if.then99.i:                                      ; preds = %if.end96.i
+  tail call void (i8*, ...) @cli_dbgmsg(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str.6, i64 0, i64 0), i32 undef)
+  br label %cleanup
+
+if.end287.i:                                      ; preds = %if.end96.i
+  %cmp291.i = icmp ne i32 undef, 1
+  %conv294.i = select i1 %cmp291.i, i16 4, i16 3
+  br i1 undef, label %if.end308.i, label %outer_loop_latch
+
+if.end308.i:                                      ; preds = %if.end287.i
+  br i1 undef, label %if.end335.i, label %merge_predecessor_split
+
+merge_predecessor_split:                          ; preds = %if.end308.i
+  %4 = bitcast i8* undef to i32*
+  br label %outer_loop_latch
+
+if.end335.i:                                      ; preds = %if.end308.i
+  br i1 undef, label %outer_loop_latch, label %merge_other
+
+merge_other:                                      ; preds = %if.end335.i
+  br label %outer_loop_latch
+
+outer_loop_latch:                                 ; preds = %merge_other, %if.end335.i, %merge_predecessor_split, %if.end287.i
+  %bits.43.i = phi i8 [ undef, %if.end287.i ], [ undef, %merge_other ], [ 32, %merge_predecessor_split ], [ 0, %if.end335.i ]
+  %backsize.0.i = phi i16 [ %conv294.i, %if.end287.i ], [ 0, %merge_other ], [ 0, %merge_predecessor_split ], [ 0, %if.end335.i ]
+  %5 = add i16 %backsize.0.i, -1
+  %6 = zext i16 %5 to i64
+  %scevgep.i = getelementptr i8, i8* %dst.0.ph.i, i64 1
+  %scevgep679.i = getelementptr i8, i8* %scevgep.i, i64 %6
+  br label %outer_loop_header
+
+wunpsect.exit.thread.loopexit389:                 ; preds = %shared_loop_header
+  unreachable
+
+wunpsect.exit.thread.loopexit391:                 ; preds = %if.end50
+  unreachable
+
+cleanup:                                          ; preds = %if.then99.i, %while.cond.us1412.i, %if.end19, %entry
+  %retval.0 = phi i32 [ 0, %if.then99.i ], [ 1, %entry ], [ 1, %if.end19 ], [ 1, %while.cond.us1412.i ]
+  ret i32 %retval.0
+}
+
+; Function Attrs: nounwind
+declare void @cli_dbgmsg(i8*, ...) local_unnamed_addr #0
+
+; Function Attrs: nounwind
+declare i8* @cli_calloc(i64, i64) local_unnamed_addr #0
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32, i1) #1
+attributes #0 = { nounwind }
+attributes #1 = { argmemonly nounwind }