[llvm-commits] [llvm] r86524 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/intrinsics.ll
Chris Lattner
sabre at nondot.org
Sun Nov 8 23:07:57 PST 2009
Author: lattner
Date: Mon Nov 9 01:07:56 2009
New Revision: 86524
URL: http://llvm.org/viewvc/llvm-project?rev=86524&view=rev
Log:
if a 'with overflow' intrinsic just has the normal result used, simplify
it to a normal binop. Patch by Alastair Lynn, testcase by me.
Added:
llvm/trunk/test/Transforms/InstCombine/intrinsics.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=86524&r1=86523&r2=86524&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Mon Nov 9 01:07:56 2009
@@ -12452,6 +12452,47 @@
return ExtractValueInst::Create(IV->getInsertedValueOperand(),
exti, exte);
}
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Agg)) {
+ // We're extracting from an intrinsic, see if we're the only user, which
+ // allows us to simplify multiple result intrinsics to simpler things that
+ // just get one value..
+ if (II->hasOneUse()) {
+ // Check if we're grabbing the overflow bit or the result of a 'with
+ // overflow' intrinsic. If it's the latter we can remove the intrinsic
+ // and replace it with a traditional binary instruction.
+ switch (II->getIntrinsicID()) {
+ case Intrinsic::uadd_with_overflow:
+ case Intrinsic::sadd_with_overflow:
+ if (*EV.idx_begin() == 0) { // Normal result.
+ Value *LHS = II->getOperand(1), *RHS = II->getOperand(2);
+ II->replaceAllUsesWith(UndefValue::get(II->getType()));
+ EraseInstFromFunction(*II);
+ return BinaryOperator::CreateAdd(LHS, RHS);
+ }
+ break;
+ case Intrinsic::usub_with_overflow:
+ case Intrinsic::ssub_with_overflow:
+ if (*EV.idx_begin() == 0) { // Normal result.
+ Value *LHS = II->getOperand(1), *RHS = II->getOperand(2);
+ II->replaceAllUsesWith(UndefValue::get(II->getType()));
+ EraseInstFromFunction(*II);
+ return BinaryOperator::CreateSub(LHS, RHS);
+ }
+ break;
+ case Intrinsic::umul_with_overflow:
+ case Intrinsic::smul_with_overflow:
+ if (*EV.idx_begin() == 0) { // Normal result.
+ Value *LHS = II->getOperand(1), *RHS = II->getOperand(2);
+ II->replaceAllUsesWith(UndefValue::get(II->getType()));
+ EraseInstFromFunction(*II);
+ return BinaryOperator::CreateMul(LHS, RHS);
+ }
+ break;
+ default:
+ break;
+ }
+ }
+ }
// Can't simplify extracts from other values. Note that nested extracts are
// already simplified implicitely by the above (extract ( extract (insert) )
// will be translated into extract ( insert ( extract ) ) first and then just
Added: llvm/trunk/test/Transforms/InstCombine/intrinsics.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/intrinsics.ll?rev=86524&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/intrinsics.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/intrinsics.ll Mon Nov 9 01:07:56 2009
@@ -0,0 +1,12 @@
+; RUN: opt %s -instcombine -S | FileCheck %s
+
+declare {i8, i1} @llvm.uadd.with.overflow.i8(i8, i8)
+
+define i8 @test1(i8 %A, i8 %B) {
+ %x = call {i8, i1} @llvm.uadd.with.overflow.i8(i8 %A, i8 %B)
+ %y = extractvalue {i8, i1} %x, 0
+ ret i8 %y
+; CHECK: @test1
+; CHECK-NEXT: %y = add i8 %A, %B
+; CHECK-NEXT: ret i8 %y
+}
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