diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 3 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/icmp.ll | 13 |
2 files changed, 16 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index 7b59f86d1ea..9a31de4f8aa 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -1950,6 +1950,9 @@ Instruction *InstCombiner::foldICmpShlConstant(ICmpInst &Cmp, And, Constant::getNullValue(And->getType())); } + // FIXME: This transform can create illegal types. Use the DataLayout to + // decide when to try this? + // Transform (icmp pred iM (shl iM %v, N), C) // -> (icmp pred i(M-N) (trunc %v iM to i(M-N)), (trunc (C>>N)) // Transform the shl to a trunc if (trunc (C>>N)) has no loss and M-N. diff --git a/llvm/test/Transforms/InstCombine/icmp.ll b/llvm/test/Transforms/InstCombine/icmp.ll index da5913e3821..57e02a47e55 100644 --- a/llvm/test/Transforms/InstCombine/icmp.ll +++ b/llvm/test/Transforms/InstCombine/icmp.ll @@ -1208,6 +1208,19 @@ define i1 @icmp_shl16(i32 %x) { ret i1 %cmp } +; FIXME: We shouldn't be creating illegal types like i15 in InstCombine. + +define i1 @icmp_shl17(i32 %x) { +; CHECK-LABEL: @icmp_shl17( +; CHECK-NEXT: [[TMP1:%.*]] = trunc i32 %x to i15 +; CHECK-NEXT: [[CMP:%.*]] = icmp slt i15 [[TMP1]], 18 +; CHECK-NEXT: ret i1 [[CMP]] +; + %shl = shl i32 %x, 17 + %cmp = icmp slt i32 %shl, 2359296 + ret i1 %cmp +} + define <2 x i1> @icmp_shl16_vec(<2 x i32> %x) { ; CHECK-LABEL: @icmp_shl16_vec( ; CHECK-NEXT: [[TMP1:%.*]] = trunc <2 x i32> %x to <2 x i16> |
