From 0ed2fdb5afffca1117b9b65736890d84e6fe7b3c Mon Sep 17 00:00:00 2001 From: Nadav Rotem Date: Tue, 12 Nov 2013 22:38:59 +0000 Subject: Fold (iszero(A&K1) | iszero(A&K2)) -> (A&(K1|K2)) != (K1|K2) if we know that K1 and K2 are 'one-hot' (only one bit is on). llvm-svn: 194525 --- llvm/test/Transforms/InstCombine/onehot_merge.ll | 35 ++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 llvm/test/Transforms/InstCombine/onehot_merge.ll (limited to 'llvm/test/Transforms') diff --git a/llvm/test/Transforms/InstCombine/onehot_merge.ll b/llvm/test/Transforms/InstCombine/onehot_merge.ll new file mode 100644 index 00000000000..51f955c2c24 --- /dev/null +++ b/llvm/test/Transforms/InstCombine/onehot_merge.ll @@ -0,0 +1,35 @@ +; RUN: opt < %s -instcombine -S | FileCheck %s + +;CHECK: @and_consts +;CHECK: and i32 %k, 12 +;CHECK: icmp ne i32 %0, 12 +;CHECK: ret +define i1 @and_consts(i32 %k, i32 %c1, i32 %c2) { +bb: + %tmp1 = and i32 4, %k + %tmp2 = icmp eq i32 %tmp1, 0 + %tmp5 = and i32 8, %k + %tmp6 = icmp eq i32 %tmp5, 0 + %or = or i1 %tmp2, %tmp6 + ret i1 %or +} + +;CHECK: @foo1_and +;CHECK: shl i32 1, %c1 +;CHECK-NEXT: shl i32 1, %c2 +;CHECK-NEXT: or i32 +;CHECK-NEXT: and i32 +;CHECK-NEXT: icmp ne i32 %1, %0 +;CHECK: ret +define i1 @foo1_and(i32 %k, i32 %c1, i32 %c2) { +bb: + %tmp = shl i32 1, %c1 + %tmp4 = shl i32 1, %c2 + %tmp1 = and i32 %tmp, %k + %tmp2 = icmp eq i32 %tmp1, 0 + %tmp5 = and i32 %tmp4, %k + %tmp6 = icmp eq i32 %tmp5, 0 + %or = or i1 %tmp2, %tmp6 + ret i1 %or +} + -- cgit v1.2.3