[llvm] b0ded70 - [LoopUnroll] Add test for mis-compile due to missing SCEV invalidation.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2022-10-18T14:56:44+01:00
New Revision: b0ded70ebf5ac3f24ebcbf7c72eea93400ec7754

URL: https://github.com/llvm/llvm-project/commit/b0ded70ebf5ac3f24ebcbf7c72eea93400ec7754
DIFF: https://github.com/llvm/llvm-project/commit/b0ded70ebf5ac3f24ebcbf7c72eea93400ec7754.diff

LOG: [LoopUnroll] Add test for mis-compile due to missing SCEV invalidation.

Test for #58340.

Added: 
    llvm/test/Transforms/LoopUnroll/scev-forget-exit-phis.ll

Modified: 
    

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/LoopUnroll/scev-forget-exit-phis.ll b/llvm/test/Transforms/LoopUnroll/scev-forget-exit-phis.ll
new file mode 100644
index 0000000000000..8cf482953f646
--- /dev/null
+++ b/llvm/test/Transforms/LoopUnroll/scev-forget-exit-phis.ll
@@ -0,0 +1,89 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes='loop(indvars,loop-unroll-full)' -S %s | FileCheck %s
+
+; FIXME: The function is mis-compiled at the moment,
+; store i64 [[SEL_2_LCSSA]], ptr [[DST_2:%.*]] writes the wrong value.
+define i8 @test_pr58340(ptr %dst.1, ptr %dst.2) {
+; CHECK-LABEL: @test_pr58340(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[OUTER_HEADER:%.*]]
+; CHECK:       outer.header:
+; CHECK-NEXT:    br label [[INNER_1_HEADER:%.*]]
+; CHECK:       inner.1.header:
+; CHECK-NEXT:    br i1 true, label [[MERGE:%.*]], label [[THEN:%.*]]
+; CHECK:       then:
+; CHECK-NEXT:    br label [[MERGE]]
+; CHECK:       merge:
+; CHECK-NEXT:    [[SEL_1:%.*]] = phi i32 [ 0, [[INNER_1_HEADER]] ], [ 2, [[THEN]] ]
+; CHECK-NEXT:    store i32 [[SEL_1]], ptr [[DST_1:%.*]], align 4
+; CHECK-NEXT:    br label [[INNER_1_LATCH:%.*]]
+; CHECK:       inner.2.header.preheader:
+; CHECK-NEXT:    [[SEL_1_LCSSA:%.*]] = phi i32 [ [[SEL_1_1:%.*]], [[MERGE_1:%.*]] ]
+; CHECK-NEXT:    br label [[INNER_2_HEADER:%.*]]
+; CHECK:       inner.1.latch:
+; CHECK-NEXT:    br i1 false, label [[MERGE_1]], label [[THEN_1:%.*]]
+; CHECK:       then.1:
+; CHECK-NEXT:    br label [[MERGE_1]]
+; CHECK:       merge.1:
+; CHECK-NEXT:    [[SEL_1_1]] = phi i32 [ 0, [[INNER_1_LATCH]] ], [ 2, [[THEN_1]] ]
+; CHECK-NEXT:    store i32 [[SEL_1_1]], ptr [[DST_1]], align 4
+; CHECK-NEXT:    br i1 false, label [[INNER_1_LATCH_1:%.*]], label [[INNER_2_HEADER_PREHEADER:%.*]]
+; CHECK:       inner.1.latch.1:
+; CHECK-NEXT:    unreachable
+; CHECK:       inner.2.header:
+; CHECK-NEXT:    br label [[INNER_3:%.*]]
+; CHECK:       inner.3:
+; CHECK-NEXT:    [[SEL_2:%.*]] = phi i64 [ [[SEL_1_EXT:%.*]], [[INNER_3]] ], [ 0, [[INNER_2_HEADER]] ]
+; CHECK-NEXT:    [[C_1:%.*]] = icmp ult i32 [[SEL_1_LCSSA]], 1
+; CHECK-NEXT:    [[SEL_1_EXT]] = sext i32 [[SEL_1_LCSSA]] to i64
+; CHECK-NEXT:    br i1 [[C_1]], label [[INNER_3]], label [[INNER_2_LATCH:%.*]]
+; CHECK:       inner.2.latch:
+; CHECK-NEXT:    [[SEL_2_LCSSA:%.*]] = phi i64 [ [[SEL_2]], [[INNER_3]] ]
+; CHECK-NEXT:    store i32 0, ptr [[DST_1]], align 4
+; CHECK-NEXT:    store i64 [[SEL_2_LCSSA]], ptr [[DST_2:%.*]], align 8
+; CHECK-NEXT:    call void @clobber()
+; CHECK-NEXT:    br label [[OUTER_HEADER]]
+;
+entry:
+  br label %outer.header
+
+outer.header:
+  %p.1 = phi i64 [ 0, %entry ], [ %sel.2, %outer.latch ]
+  br label %inner.1.header
+
+inner.1.header:
+  %p.2 = phi i64 [ %p.1, %outer.header ], [ 0, %inner.1.latch ]
+  %b = phi i1 [ true, %outer.header ], [ false, %inner.1.latch ]
+  br i1 %b, label %merge, label %then
+
+then:
+  br label %merge
+
+merge:
+  %sel.1 = phi i32 [ 0, %inner.1.header ], [ 2, %then ]
+  store i32 %sel.1, ptr %dst.1, align 4
+  br i1 %b, label %inner.1.latch, label %inner.2.header
+
+inner.1.latch:
+  br label %inner.1.header
+
+inner.2.header:
+  br label %inner.3
+
+inner.3:
+  %sel.2 = phi i64 [ %sel.1.ext, %inner.3 ], [ 0, %inner.2.header ]
+  %c.1 = icmp ult i32 %sel.1, 1
+  %sel.1.ext = sext i32 %sel.1 to i64
+  br i1 %c.1, label %inner.3, label %inner.2.latch
+
+inner.2.latch:
+  br i1 false, label %inner.2.header, label %outer.latch
+
+outer.latch:
+  store i32 0, ptr %dst.1, align 4
+  store i64 %sel.2, ptr %dst.2, align 8
+  call void @clobber()
+  br label %outer.header
+}
+
+declare void @clobber()