commit e812ca00bbd50be94f9e0110be5f99b72b2efc07
author Artur Pilipenko <apilipenko@azulsystems.com> Wed Jan 25 14:12:12 2017 +0000
committer Artur Pilipenko <apilipenko@azulsystems.com> Wed Jan 25 14:12:12 2017 +0000
tree c8f6629ad29b090d2cf9507f6e2503b5ea572a5e
parent 91834227a3d58ecdb9e3f7300f587ab45c32ba06

[InstCombine] Allow InstrCombine to remove one of adjacent guards if they are equivalent

This is a partial fix for Bug 31520 - [guards] canonicalize guards in instcombine

Reviewed By: majnemer, apilipenko

Differential Revision: https://reviews.llvm.org/D29071

Patch by Maxim Kazantsev.

llvm-svn: 293056

llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 6b03b68..6795967 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2870,6 +2870,16 @@
     // TODO: relocate((gep p, C, C2, ...)) -> gep(relocate(p), C, C2, ...)
     break;
   }
+
+  case Intrinsic::experimental_guard: {
+    Value *IIOperand = II->getArgOperand(0);
+
+    // Remove a guard if it is immediately followed by an identical guard.
+    if (match(II->getNextNode(),
+              m_Intrinsic<Intrinsic::experimental_guard>(m_Specific(IIOperand))))
+      return eraseInstFromFunction(*II);
+    break;
+  }
   }
 
   return visitCallSite(II);

llvm/test/Transforms/InstCombine/call-guard.ll

diff --git a/llvm/test/Transforms/InstCombine/call-guard.ll b/llvm/test/Transforms/InstCombine/call-guard.ll
new file mode 100644
index 0000000..18da465
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/call-guard.ll
@@ -0,0 +1,30 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+declare void @llvm.experimental.guard(i1, ...)
+
+define void @test_guard_adjacent(i1 %A) {
+; CHECK-LABEL: @test_guard_adjacent(
+; CHECK-NEXT:    call void (i1, ...) @llvm.experimental.guard(i1 %A) [ "deopt"() ]
+; CHECK-NEXT:    ret void
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  ret void
+}
+
+define void @test_guard_adjacent_neg(i1 %A, i1 %B) {
+; CHECK-LABEL: @test_guard_adjacent_neg(
+; CHECK-NEXT:    call void (i1, ...) @llvm.experimental.guard(i1 %A) [ "deopt"() ]
+; CHECK-NEXT:    call void (i1, ...) @llvm.experimental.guard(i1 %B) [ "deopt"() ]
+; CHECK-NEXT:    ret void
+  call void(i1, ...) @llvm.experimental.guard( i1 %A )[ "deopt"() ]
+  call void(i1, ...) @llvm.experimental.guard( i1 %B )[ "deopt"() ]
+  ret void
+}