maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/llvm/test/CodeGen/X86/shift-i256.ll

22 lines
614 B
LLVM
Raw Normal View History

X86: Do not use llc -march in tests. `llc -march` is problematic because it only switches the target architecture, but leaves the operating system unchanged. This occasionally leads to indeterministic tests because the OS from LLVM_DEFAULT_TARGET_TRIPLE is used. However we can simply always use `llc -mtriple` instead. This changes all the tests to do this to avoid people using -march when they copy and paste parts of tests. See also the discussion in https://reviews.llvm.org/D35287 llvm-svn: 309774
2017-08-02 08:28:10 +08:00
; RUN: llc < %s -mtriple=i686-- | FileCheck %s
; RUN: llc < %s -mtriple=x86_64-- -O0 | FileCheck %s -check-prefix=CHECK-X64
; RUN: llc < %s -mtriple=x86_64-- -O2 | FileCheck %s -check-prefix=CHECK-X64
Fully general expansion of integer shift of any size. llvm-svn: 68134
2009-04-01 03:39:24 +08:00
Fix generic shift expansion when shift amount is 0 Summary: This fixes http://llvm.org/bugs/show_bug.cgi?id=16439. This is one possible way to approach this. The other would be to split InL>>(nbits-Amt) into (InL>>(nbits-1-Amt))>>1, which is also valid since since we only need to care about Amt up nbits-1. It's hard to tell which one is better since the shift might be expensive if this stage of expansion is not yet a legal machine integer, whereas comparisons with zero are relatively cheap at all sizes, but more expensive than a shift if the shift is on a legal machine type. Patch by Keno Fischer! Test Plan: regression test from http://reviews.llvm.org/D7752 Reviewers: chfast, resistor Reviewed By: chfast, resistor Subscribers: sanjoy, resistor, chfast, llvm-commits Differential Revision: http://reviews.llvm.org/D4978 llvm-svn: 235370
2015-04-21 14:28:36 +08:00
; CHECK-LABEL: shift1
define void @shift1(i256 %x, i256 %a, i256* nocapture %r) nounwind readnone {
Fully general expansion of integer shift of any size. llvm-svn: 68134
2009-04-01 03:39:24 +08:00
entry:
%0 = ashr i256 %x, %a
store i256 %0, i256* %r
ret void
}
Fix generic shift expansion when shift amount is 0 Summary: This fixes http://llvm.org/bugs/show_bug.cgi?id=16439. This is one possible way to approach this. The other would be to split InL>>(nbits-Amt) into (InL>>(nbits-1-Amt))>>1, which is also valid since since we only need to care about Amt up nbits-1. It's hard to tell which one is better since the shift might be expensive if this stage of expansion is not yet a legal machine integer, whereas comparisons with zero are relatively cheap at all sizes, but more expensive than a shift if the shift is on a legal machine type. Patch by Keno Fischer! Test Plan: regression test from http://reviews.llvm.org/D7752 Reviewers: chfast, resistor Reviewed By: chfast, resistor Subscribers: sanjoy, resistor, chfast, llvm-commits Differential Revision: http://reviews.llvm.org/D4978 llvm-svn: 235370
2015-04-21 14:28:36 +08:00
; CHECK-LABEL: shift2
define i256 @shift2(i256 %c) nounwind
{
%b = shl i256 1, %c ; %c must not be a constant
; Special case when %c is 0:
; CHECK-X64: testb [[REG:%r[0-9]+b]], [[REG]]
; CHECK-X64: cmoveq
ret i256 %b
}