[llvm] r320983 - [LVI] Support for ashr in LVI

[Max Kazantsev via llvm-commits]

Author: mkazantsev
Date: Mon Dec 18 06:23:30 2017
New Revision: 320983

URL: http://llvm.org/viewvc/llvm-project?rev=320983&view=rev
Log:
[LVI] Support for ashr in LVI

Enhance LVI to analyze the ‘ashr’ binary operation. This leverages the infrastructure in ConstantRange for the ashr operation.

Patch by Surya Kumari Jangala!

Differential Revision: https://reviews.llvm.org/D40886

Added:
    llvm/trunk/test/Analysis/LazyValueAnalysis/lvi-for-ashr.ll
Modified:
    llvm/trunk/lib/Analysis/LazyValueInfo.cpp

Modified: llvm/trunk/lib/Analysis/LazyValueInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LazyValueInfo.cpp?rev=320983&r1=320982&r2=320983&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LazyValueInfo.cpp (original)
+++ llvm/trunk/lib/Analysis/LazyValueInfo.cpp Mon Dec 18 06:23:30 2017
@@ -1002,6 +1002,7 @@ bool LazyValueInfoImpl::solveBlockValueB
   case Instruction::UDiv:
   case Instruction::Shl:
   case Instruction::LShr:
+  case Instruction::AShr:
   case Instruction::And:
   case Instruction::Or:
     // continue into the code below

Added: llvm/trunk/test/Analysis/LazyValueAnalysis/lvi-for-ashr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/LazyValueAnalysis/lvi-for-ashr.ll?rev=320983&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/LazyValueAnalysis/lvi-for-ashr.ll (added)
+++ llvm/trunk/test/Analysis/LazyValueAnalysis/lvi-for-ashr.ll Mon Dec 18 06:23:30 2017
@@ -0,0 +1,27 @@
+; RUN: opt -correlated-propagation -S %s | FileCheck %s
+; CHECK-LABEL: @test-ashr
+; CHECK: bb_then
+; CHECK:  %. = select i1 true, i32 3, i32 2
+define i32 @test-ashr(i32 %c) {
+chk65:
+  %cmp = icmp sgt i32 %c, 65
+  br i1 %cmp, label %return, label %chk0
+
+chk0:
+  %cmp1 = icmp slt i32 %c, 0
+  br i1 %cmp, label %return, label %bb_if
+
+bb_if:
+  %ashr.val = ashr exact i32 %c, 2
+  %cmp2 = icmp sgt i32 %ashr.val, 15
+  br i1 %cmp2, label %bb_then, label %return
+
+bb_then:
+  %cmp3 = icmp eq i32 %ashr.val, 16
+  %. = select i1 %cmp3, i32 3, i32 2
+  br label %return
+
+return:
+  %retval = phi i32 [0, %chk65], [1, %chk0], [%., %bb_then], [4, %bb_if]
+  ret i32 %retval
+}