From ed1088afb51189efff02886891c4e25a5a5fb5f9 Mon Sep 17 00:00:00 2001 From: Owen Anderson Date: Wed, 22 Sep 2010 22:58:22 +0000 Subject: A select between a constant and zero, when fed by a bit test, can be efficiently lowered using a series of shifts. Fixes . git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114599 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/CodeGen/X86/bit-test-shift.ll | 13 +++++++++++++ 1 file changed, 13 insertions(+) create mode 100644 test/CodeGen/X86/bit-test-shift.ll (limited to 'test') diff --git a/test/CodeGen/X86/bit-test-shift.ll b/test/CodeGen/X86/bit-test-shift.ll new file mode 100644 index 0000000000..7497613f25 --- /dev/null +++ b/test/CodeGen/X86/bit-test-shift.ll @@ -0,0 +1,13 @@ +; RUN: llc < %s -march=x86 | FileCheck %s +; + +define i32 @x(i32 %t) nounwind readnone ssp { +entry: +; CHECK: shll $23, %eax +; CHECK: sarl $31, %eax +; CHECK: andl $-26, %eax + %and = and i32 %t, 256 + %tobool = icmp eq i32 %and, 0 + %retval.0 = select i1 %tobool, i32 0, i32 -26 + ret i32 %retval.0 +} -- cgit v1.2.3