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| author | David Majnemer <david.majnemer@gmail.com> | 2014-08-22 00:40:43 +0000 |
|---|---|---|
| committer | David Majnemer <david.majnemer@gmail.com> | 2014-08-22 00:40:43 +0000 |
| commit | 97ddca3224e13760bd3936188585074d10caafb6 (patch) | |
| tree | 80474f18e524a55d11850aabcb366d542fb78607 /llvm/test/Transforms | |
| parent | ffe5e5a42d929e3fd8fe5226822fd73c4ce8b389 (diff) | |
| download | bcm5719-llvm-97ddca3224e13760bd3936188585074d10caafb6.tar.gz bcm5719-llvm-97ddca3224e13760bd3936188585074d10caafb6.zip | |
ValueTracking: Figure out more bits when looking at add/sub
Given something like X01XX + X01XX, we know that the result must look
like X1XXX.
Adapted from a patch by Richard Smith, test-case written by me.
llvm-svn: 216250
Diffstat (limited to 'llvm/test/Transforms')
| -rw-r--r-- | llvm/test/Transforms/InstSimplify/compare.ll | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/llvm/test/Transforms/InstSimplify/compare.ll b/llvm/test/Transforms/InstSimplify/compare.ll index 94872d35bb9..27fe1bead23 100644 --- a/llvm/test/Transforms/InstSimplify/compare.ll +++ b/llvm/test/Transforms/InstSimplify/compare.ll @@ -969,3 +969,16 @@ define i1 @icmp_sdiv_neg1(i64 %a) { ; CHECK-NEXT: [[CMP:%.*]] = icmp ne i64 [[DIV]], 1073741824 ; CHECK-NEXT: ret i1 [[CMP]] } + +define i1 @icmp_known_bits(i4 %x, i4 %y) { + %and1 = and i4 %y, -7 + %and2 = and i4 %x, -7 + %or1 = or i4 %and1, 2 + %or2 = or i4 %and2, 2 + %add = add i4 %or1, %or2 + %cmp = icmp eq i4 %add, 0 + ret i1 %cmp + +; CHECK-LABEL: @icmp_known_bits +; CHECK-NEXT: ret i1 false +} |
