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| -rw-r--r-- | llvm/test/Transforms/InstSimplify/constantfold-add-nuw-allones-to-allones.ll | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/llvm/test/Transforms/InstSimplify/constantfold-add-nuw-allones-to-allones.ll b/llvm/test/Transforms/InstSimplify/constantfold-add-nuw-allones-to-allones.ll new file mode 100644 index 00000000000..68db8cef8eb --- /dev/null +++ b/llvm/test/Transforms/InstSimplify/constantfold-add-nuw-allones-to-allones.ll @@ -0,0 +1,145 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt < %s -instsimplify -S | FileCheck %s + +; %ret = add nuw i8 %x, C +; nuw means no unsigned wrap, from -1 to 0. +; So if C is -1, %x can only be 0, and the result is always -1. + +define i8 @add_nuw (i8 %x) { +; CHECK-LABEL: @add_nuw( +; CHECK-NEXT: [[RET:%.*]] = add nuw i8 [[X:%.*]], -1 +; CHECK-NEXT: ret i8 [[RET]] +; + %ret = add nuw i8 %x, -1 + ; nuw here means that %x can only be 0 + ret i8 %ret +} + +define i8 @add_nuw_nsw (i8 %x) { +; CHECK-LABEL: @add_nuw_nsw( +; CHECK-NEXT: [[RET:%.*]] = add nuw nsw i8 [[X:%.*]], -1 +; CHECK-NEXT: ret i8 [[RET]] +; + %ret = add nuw nsw i8 %x, -1 + ; nuw here means that %x can only be 0 + ret i8 %ret +} + +define i8 @add_nuw_commute (i8 %x) { +; CHECK-LABEL: @add_nuw_commute( +; CHECK-NEXT: [[RET:%.*]] = add nuw i8 -1, [[X:%.*]] +; CHECK-NEXT: ret i8 [[RET]] +; + %ret = add nuw i8 -1, %x ; swapped + ; nuw here means that %x can only be 0 + ret i8 %ret +} + +; ============================================================================ ; +; Positive tests with value range known +; ============================================================================ ; + +declare void @llvm.assume(i1 %cond); + +define i8 @knownbits_allones(i8 %x, i8 %y) { +; CHECK-LABEL: @knownbits_allones( +; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[Y:%.*]], -2 +; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]]) +; CHECK-NEXT: [[RET:%.*]] = add nuw i8 [[X:%.*]], [[Y]] +; CHECK-NEXT: ret i8 [[RET]] +; + %cmp = icmp slt i8 %y, 254 + tail call void @llvm.assume(i1 %cmp) + %ret = add nuw i8 %x, %y + ret i8 %ret +} + +; ============================================================================ ; +; Vectors +; ============================================================================ ; + +define <2 x i8> @add_vec(<2 x i8> %x) { +; CHECK-LABEL: @add_vec( +; CHECK-NEXT: [[RET:%.*]] = add nuw <2 x i8> [[X:%.*]], <i8 -1, i8 -1> +; CHECK-NEXT: ret <2 x i8> [[RET]] +; + %ret = add nuw <2 x i8> %x, <i8 -1, i8 -1> + ret <2 x i8> %ret +} + +define <3 x i8> @add_vec_undef(<3 x i8> %x) { +; CHECK-LABEL: @add_vec_undef( +; CHECK-NEXT: [[RET:%.*]] = add nuw <3 x i8> [[X:%.*]], <i8 -1, i8 undef, i8 -1> +; CHECK-NEXT: ret <3 x i8> [[RET]] +; + %ret = add nuw <3 x i8> %x, <i8 -1, i8 undef, i8 -1> + ret <3 x i8> %ret +} + +; ============================================================================ ; +; Negative tests. Should not be folded. +; ============================================================================ ; + +define i8 @bad_add (i8 %x) { +; CHECK-LABEL: @bad_add( +; CHECK-NEXT: [[RET:%.*]] = add i8 [[X:%.*]], -1 +; CHECK-NEXT: ret i8 [[RET]] +; + %ret = add i8 %x, -1 ; need nuw + ret i8 %ret +} + +define i8 @bad_add_nsw (i8 %x) { +; CHECK-LABEL: @bad_add_nsw( +; CHECK-NEXT: [[RET:%.*]] = add nsw i8 [[X:%.*]], -1 +; CHECK-NEXT: ret i8 [[RET]] +; + %ret = add nsw i8 %x, -1 ; need nuw + ret i8 %ret +} + +; Second `add` operand is not `-1` constant + +define i8 @bad_add0(i8 %x, i8 %addop2) { +; CHECK-LABEL: @bad_add0( +; CHECK-NEXT: [[RET:%.*]] = add nuw i8 [[X:%.*]], [[ADDOP2:%.*]] +; CHECK-NEXT: ret i8 [[RET]] +; + %ret = add nuw i8 %x, %addop2 + ret i8 %ret +} + +; Bad constant + +define i8 @bad_add1(i8 %x) { +; CHECK-LABEL: @bad_add1( +; CHECK-NEXT: [[RET:%.*]] = add nuw i8 [[X:%.*]], 1 +; CHECK-NEXT: ret i8 [[RET]] +; + %ret = add nuw i8 %x, 1 ; not -1 + ret i8 %ret +} + +define <2 x i8> @bad_add_vec_nonsplat(<2 x i8> %x) { +; CHECK-LABEL: @bad_add_vec_nonsplat( +; CHECK-NEXT: [[RET:%.*]] = add nuw <2 x i8> [[X:%.*]], <i8 -1, i8 1> +; CHECK-NEXT: ret <2 x i8> [[RET]] +; + %ret = add nuw <2 x i8> %x, <i8 -1, i8 1> + ret <2 x i8> %ret +} + +; Bad known bits + +define i8 @bad_knownbits(i8 %x, i8 %y) { +; CHECK-LABEL: @bad_knownbits( +; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[X:%.*]], -3 +; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]]) +; CHECK-NEXT: [[RET:%.*]] = add nuw i8 [[X]], [[Y:%.*]] +; CHECK-NEXT: ret i8 [[RET]] +; + %cmp = icmp slt i8 %x, 253 + tail call void @llvm.assume(i1 %cmp) + %ret = add nuw i8 %x, %y + ret i8 %ret +} |
