Author: Roman Lebedev Date: 2020-02-27T13:45:21+01:00 New Revision: ac293ede5e62cfc569f2d5d8f4667e6188afced0
URL: https://github.com/llvm/llvm-project/commit/ac293ede5e62cfc569f2d5d8f4667e6188afced0 DIFF: https://github.com/llvm/llvm-project/commit/ac293ede5e62cfc569f2d5d8f4667e6188afced0.diff LOG: [NFC][InstCombine] Add shift amount reassociation in bittest miscompile example from PR44802 https://bugs.llvm.org/show_bug.cgi?id=44802 (cherry picked from commit 6f807ca00d951d3e74f7ea4fe1daa8e3560f4c0d) Added: Modified: llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll Removed: ################################################################################ diff --git a/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll b/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll index 27224705929c..0386d8042f92 100644 --- a/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll +++ b/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll @@ -687,3 +687,20 @@ entry: %tobool = icmp ne i16 %and, 0 ret i1 %tobool } + +; FIXME: this is a miscompile. We should not transform this. +; See https://bugs.llvm.org/show_bug.cgi?id=44802 +define i1 @pr44802(i3 %a, i3 %x, i3 %y) { +; CHECK-LABEL: @pr44802( +; CHECK-NEXT: [[TMP1:%.*]] = and i3 [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i3 [[TMP1]], 0 +; CHECK-NEXT: ret i1 [[TMP2]] +; + %t0 = icmp ne i3 %a, 0 + %t1 = zext i1 %t0 to i3 + %t2 = lshr i3 %x, %t1 + %t3 = shl i3 %y, %t1 + %t4 = and i3 %t2, %t3 + %t5 = icmp ne i3 %t4, 0 + ret i1 %t5 +} _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
