From edba515baa3d924000f9704890987aaad5d90630 Mon Sep 17 00:00:00 2001 From: Roman Lebedev Date: Sat, 14 Jul 2018 20:08:42 +0000 Subject: [PATCH] [NFC][InstCombine] Tests for x & (-1 >> y) s< x to x s> (-1 >> y) fold. https://bugs.llvm.org/show_bug.cgi?id=38123 https://rise4fun.com/Alive/I3O This pattern is not commutative! We must make sure not to fold the commuted version! llvm-svn: 337110 --- ...nstant-low-bit-mask-and-icmp-slt-to-icmp-sgt.ll | 204 +++++++++++++++++++++ 1 file changed, 204 insertions(+) create mode 100644 llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-slt-to-icmp-sgt.ll diff --git a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-slt-to-icmp-sgt.ll b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-slt-to-icmp-sgt.ll new file mode 100644 index 0000000..c5e981b --- /dev/null +++ b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-slt-to-icmp-sgt.ll @@ -0,0 +1,204 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt < %s -instcombine -S | FileCheck %s + +; https://bugs.llvm.org/show_bug.cgi?id=38123 + +; Pattern: +; x & C s< x +; Should be transformed into: +; x s> C +; Iff: isPowerOf2(C + 1) + +; ============================================================================ ; +; Basic positive tests +; ============================================================================ ; + +define i1 @p0(i8 %x) { +; CHECK-LABEL: @p0( +; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X:%.*]], 3 +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[TMP0]], [[X]] +; CHECK-NEXT: ret i1 [[RET]] +; + %tmp0 = and i8 %x, 3 + %ret = icmp slt i8 %tmp0, %x + ret i1 %ret +} + +define i1 @pv(i8 %x, i8 %y) { +; CHECK-LABEL: @pv( +; CHECK-NEXT: [[TMP0:%.*]] = lshr i8 -1, [[Y:%.*]] +; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[TMP0]], [[X:%.*]] +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[TMP1]], [[X]] +; CHECK-NEXT: ret i1 [[RET]] +; + %tmp0 = lshr i8 -1, %y + %tmp1 = and i8 %tmp0, %x + %ret = icmp slt i8 %tmp1, %x + ret i1 %ret +} + +; ============================================================================ ; +; Vector tests +; ============================================================================ ; + +define <2 x i1> @p1_vec_splat(<2 x i8> %x) { +; CHECK-LABEL: @p1_vec_splat( +; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X:%.*]], +; CHECK-NEXT: [[RET:%.*]] = icmp slt <2 x i8> [[TMP0]], [[X]] +; CHECK-NEXT: ret <2 x i1> [[RET]] +; + %tmp0 = and <2 x i8> %x, + %ret = icmp slt <2 x i8> %tmp0, %x + ret <2 x i1> %ret +} + +define <2 x i1> @p2_vec_nonsplat(<2 x i8> %x) { +; CHECK-LABEL: @p2_vec_nonsplat( +; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X:%.*]], +; CHECK-NEXT: [[RET:%.*]] = icmp slt <2 x i8> [[TMP0]], [[X]] +; CHECK-NEXT: ret <2 x i1> [[RET]] +; + %tmp0 = and <2 x i8> %x, ; doesn't have to be splat. + %ret = icmp slt <2 x i8> %tmp0, %x + ret <2 x i1> %ret +} + +define <3 x i1> @p3_vec_splat_undef(<3 x i8> %x) { +; CHECK-LABEL: @p3_vec_splat_undef( +; CHECK-NEXT: [[TMP0:%.*]] = and <3 x i8> [[X:%.*]], +; CHECK-NEXT: [[RET:%.*]] = icmp slt <3 x i8> [[TMP0]], [[X]] +; CHECK-NEXT: ret <3 x i1> [[RET]] +; + %tmp0 = and <3 x i8> %x, + %ret = icmp slt <3 x i8> %tmp0, %x + ret <3 x i1> %ret +} + +; ============================================================================ ; +; One-use tests. We don't care about multi-uses here. +; ============================================================================ ; + +declare void @use8(i8) + +define i1 @oneuse0(i8 %x) { +; CHECK-LABEL: @oneuse0( +; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X:%.*]], 3 +; CHECK-NEXT: call void @use8(i8 [[TMP0]]) +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[TMP0]], [[X]] +; CHECK-NEXT: ret i1 [[RET]] +; + %tmp0 = and i8 %x, 3 + call void @use8(i8 %tmp0) + %ret = icmp slt i8 %tmp0, %x + ret i1 %ret +} + +; ============================================================================ ; +; Negative tests +; ============================================================================ ; + +; ============================================================================ ; +; Commutativity tests. +; ============================================================================ ; + +declare i8 @gen8() + +define i1 @c0() { +; CHECK-LABEL: @c0( +; CHECK-NEXT: [[X:%.*]] = call i8 @gen8() +; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X]], 3 +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[X]], [[TMP0]] +; CHECK-NEXT: ret i1 [[RET]] +; + %x = call i8 @gen8() + %tmp0 = and i8 %x, 3 + %ret = icmp slt i8 %x, %tmp0 ; swapped order + ret i1 %ret +} + +; ============================================================================ ; +; Commutativity tests with variable +; ============================================================================ ; + +; Ok, this one should fold. We only testing commutativity of 'and'. +define i1 @cv0(i8 %y) { +; CHECK-LABEL: @cv0( +; CHECK-NEXT: [[X:%.*]] = call i8 @gen8() +; CHECK-NEXT: [[TMP0:%.*]] = lshr i8 -1, [[Y:%.*]] +; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X]], [[TMP0]] +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[TMP1]], [[X]] +; CHECK-NEXT: ret i1 [[RET]] +; + %x = call i8 @gen8() + %tmp0 = lshr i8 -1, %y + %tmp1 = and i8 %x, %tmp0 ; swapped order + %ret = icmp slt i8 %tmp1, %x + ret i1 %ret +} + +define i1 @cv1(i8 %y) { +; CHECK-LABEL: @cv1( +; CHECK-NEXT: [[X:%.*]] = call i8 @gen8() +; CHECK-NEXT: [[TMP0:%.*]] = lshr i8 -1, [[Y:%.*]] +; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[TMP0]], [[X]] +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[X]], [[TMP1]] +; CHECK-NEXT: ret i1 [[RET]] +; + %x = call i8 @gen8() + %tmp0 = lshr i8 -1, %y + %tmp1 = and i8 %tmp0, %x + %ret = icmp slt i8 %x, %tmp1 ; swapped order + ret i1 %ret +} + +define i1 @cv2(i8 %y) { +; CHECK-LABEL: @cv2( +; CHECK-NEXT: [[X:%.*]] = call i8 @gen8() +; CHECK-NEXT: [[TMP0:%.*]] = lshr i8 -1, [[Y:%.*]] +; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X]], [[TMP0]] +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[X]], [[TMP1]] +; CHECK-NEXT: ret i1 [[RET]] +; + %x = call i8 @gen8() + %tmp0 = lshr i8 -1, %y + %tmp1 = and i8 %x, %tmp0 ; swapped order + %ret = icmp slt i8 %x, %tmp1 ; swapped order + ret i1 %ret +} + +; ============================================================================ ; +; Normal negative tests +; ============================================================================ ; + +define i1 @n0(i8 %x) { +; CHECK-LABEL: @n0( +; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X:%.*]], 4 +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[TMP0]], [[X]] +; CHECK-NEXT: ret i1 [[RET]] +; + %tmp0 = and i8 %x, 4 ; power-of-two, but invalid. + %ret = icmp slt i8 %tmp0, %x + ret i1 %ret +} + +define i1 @n1(i8 %x, i8 %y, i8 %notx) { +; CHECK-LABEL: @n1( +; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X:%.*]], 3 +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[TMP0]], [[NOTX:%.*]] +; CHECK-NEXT: ret i1 [[RET]] +; + %tmp0 = and i8 %x, 3 + %ret = icmp slt i8 %tmp0, %notx ; not %x + ret i1 %ret +} + +define <2 x i1> @n2(<2 x i8> %x) { +; CHECK-LABEL: @n2( +; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X:%.*]], +; CHECK-NEXT: [[RET:%.*]] = icmp slt <2 x i8> [[TMP0]], [[X]] +; CHECK-NEXT: ret <2 x i1> [[RET]] +; + %tmp0 = and <2 x i8> %x, ; only the first one is valid. + %ret = icmp slt <2 x i8> %tmp0, %x + ret <2 x i1> %ret +} -- 2.7.4