[llvm] ed72dc8 - [IndVarSimplify] Add test for PR63763 (NFC)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2023-08-11T16:53:55+02:00
New Revision: ed72dc8c1fdae691f5d57bb2254e3922db46b7e2

URL: https://github.com/llvm/llvm-project/commit/ed72dc8c1fdae691f5d57bb2254e3922db46b7e2
DIFF: https://github.com/llvm/llvm-project/commit/ed72dc8c1fdae691f5d57bb2254e3922db46b7e2.diff

LOG: [IndVarSimplify] Add test for PR63763 (NFC)

Added: 
    llvm/test/Transforms/IndVarSimplify/pr63763.ll

Modified: 
    

Removed: 
    


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diff  --git a/llvm/test/Transforms/IndVarSimplify/pr63763.ll b/llvm/test/Transforms/IndVarSimplify/pr63763.ll
new file mode 100644
index 00000000000000..709c454e8c66db
--- /dev/null
+++ b/llvm/test/Transforms/IndVarSimplify/pr63763.ll
@@ -0,0 +1,50 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
+; RUN: opt -S -passes='print<scalar-evolution>,indvars' < %s 2>/dev/null | FileCheck %s
+
+; FIXME: This is a miscompile.
+; We should use %invariant.op.us rather than %invariant.op for the exit
+; value expansion. They have the same SCEV, but %invariant.op is more
+; poisonous.
+define i32 @test(i1 %c) {
+; CHECK-LABEL: define i32 @test
+; CHECK-SAME: (i1 [[C:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[C]], i32 33, i32 0
+; CHECK-NEXT:    [[SUB_I:%.*]] = add nsw i32 [[SEL]], -68
+; CHECK-NEXT:    [[SHL_I:%.*]] = shl nuw nsw i32 1, [[SUB_I]]
+; CHECK-NEXT:    [[ADD:%.*]] = add nsw i32 [[SHL_I]], [[SEL]]
+; CHECK-NEXT:    [[SEXT:%.*]] = shl i32 [[ADD]], 24
+; CHECK-NEXT:    [[CONV2:%.*]] = ashr exact i32 [[SEXT]], 24
+; CHECK-NEXT:    [[INVARIANT_OP:%.*]] = sub i32 7, [[CONV2]]
+; CHECK-NEXT:    call void @use(i32 [[INVARIANT_OP]])
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    br i1 true, label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i32 [[INVARIANT_OP]]
+;
+entry:
+  %sel = select i1 %c, i32 33, i32 0
+  %sub.i = add nsw i32 %sel, -68
+  %shl.i = shl nuw nsw i32 1, %sub.i
+  %add = add nsw i32 %shl.i, %sel
+  %sext = shl i32 %add, 24
+  %conv2 = ashr exact i32 %sext, 24
+  %invariant.op = sub nsw i32 7, %conv2
+  call void @use(i32 %invariant.op)
+  %sext.us = shl i32 %sel, 24
+  %conv2.us = ashr exact i32 %sext.us, 24
+  %invariant.op.us = sub nsw i32 7, %conv2.us
+  br label %loop
+
+loop:
+  %iv = phi i32 [ %iv.next , %loop ], [ 0, %entry ]
+  %iv.next = add i32 %iv, 1
+  %cmp = icmp eq i32 %iv.next, %invariant.op.us
+  br i1 %cmp, label %exit, label %loop
+
+exit:
+  ret i32 %iv.next
+}
+
+declare void @use(i32)