[llvm-commits] [llvm] r126452 - in /llvm/trunk: lib/Transforms/Utils/SimplifyCFG.cpp test/Transforms/SimplifyCFG/select-gep.ll
Benjamin Kramer
benny.kra at googlemail.com
Thu Feb 24 15:26:09 PST 2011
Author: d0k
Date: Thu Feb 24 17:26:09 2011
New Revision: 126452
URL: http://llvm.org/viewvc/llvm-project?rev=126452&view=rev
Log:
SimplifyCFG: GEPs with just one non-constant index are also cheap.
Modified:
llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
llvm/trunk/test/Transforms/SimplifyCFG/select-gep.ll
Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=126452&r1=126451&r2=126452&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Thu Feb 24 17:26:09 2011
@@ -247,11 +247,13 @@
if (PBB->getFirstNonPHIOrDbg() != I)
return false;
break;
- case Instruction::GetElementPtr:
- // GEPs are cheap if all indices are constant.
- if (!cast<GetElementPtrInst>(I)->hasAllConstantIndices())
+ case Instruction::GetElementPtr: {
+ // GEPs are cheap if all indices are constant or if there's only one index.
+ GetElementPtrInst *GEP = cast<GetElementPtrInst>(I);
+ if (!GEP->hasAllConstantIndices() && GEP->getNumIndices() > 1)
return false;
break;
+ }
case Instruction::Add:
case Instruction::Sub:
case Instruction::And:
Modified: llvm/trunk/test/Transforms/SimplifyCFG/select-gep.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/select-gep.ll?rev=126452&r1=126451&r2=126452&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/SimplifyCFG/select-gep.ll (original)
+++ llvm/trunk/test/Transforms/SimplifyCFG/select-gep.ll Thu Feb 24 17:26:09 2011
@@ -1,13 +1,13 @@
; RUN: opt -S -simplifycfg %s | FileCheck %s
-define i8* @test1(i8* %x) nounwind {
+define i8* @test1(i8* %x, i64 %y) nounwind {
entry:
%tmp1 = load i8* %x, align 1
%cmp = icmp eq i8 %tmp1, 47
br i1 %cmp, label %if.then, label %if.end
if.then:
- %incdec.ptr = getelementptr inbounds i8* %x, i64 1
+ %incdec.ptr = getelementptr inbounds i8* %x, i64 %y
br label %if.end
if.end:
@@ -18,3 +18,23 @@
; CHECK: %x.addr = select i1 %cmp, i8* %incdec.ptr, i8* %x
; CHECK: ret i8* %x.addr
}
+
+%ST = type { i8, i8 }
+
+define i8* @test2(%ST* %x, i8* %y) nounwind {
+entry:
+ %cmp = icmp eq %ST* %x, null
+ br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+ %incdec.ptr = getelementptr %ST* %x, i32 0, i32 1
+ br label %if.end
+
+if.end:
+ %x.addr = phi i8* [ %incdec.ptr, %if.then ], [ %y, %entry ]
+ ret i8* %x.addr
+
+; CHECK: @test2
+; CHECK: %x.addr = select i1 %cmp, i8* %incdec.ptr, i8* %y
+; CHECK: ret i8* %x.addr
+}
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