diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp index 365589dc0da..911545d86f3 100644 --- a/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -281,17 +281,15 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L, // If this instruction is dead now, delete it. RecursivelyDeleteTriviallyDeadInstructions(Inst); - // If we're inserting code into the exit block rather than the - // preheader, we can (and have to) remove the PHI entirely. - // This is safe, because the NewVal won't be variant - // in the loop, so we don't need an LCSSA phi node anymore. - if (ExitBlocks.size() == 1) { + if (NumPreds == 1) { + // Completely replace a single-pred PHI. This is safe, because the + // NewVal won't be variant in the loop, so we don't need an LCSSA phi + // node anymore. PN->replaceAllUsesWith(ExitVal); RecursivelyDeleteTriviallyDeadInstructions(PN); - break; } } - if (ExitBlocks.size() != 1) { + if (NumPreds != 1) { // Clone the PHI and delete the original one. This lets IVUsers and // any other maps purge the original user from their records. PHINode *NewPN = PN->clone(*Context); diff --git a/test/Transforms/IndVarSimplify/loop_evaluate10.ll b/test/Transforms/IndVarSimplify/loop_evaluate10.ll new file mode 100644 index 00000000000..37663339e43 --- /dev/null +++ b/test/Transforms/IndVarSimplify/loop_evaluate10.ll @@ -0,0 +1,47 @@ +; RUN: llvm-as < %s | opt -indvars | llvm-dis \ +; RUN: | grep {%b.1 = phi i32 \\\[ 2, %bb \\\], \\\[ 1, %bb2 \\\]} + +; This loop has multiple exits, and the value of %b1 depends on which +; exit is taken. Indvars should correctly compute the exit values. + +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128" +target triple = "x86_64-linux-gnu" + %struct..0anon = type <{ i8, [3 x i8] }> + +define i32 @main() nounwind { +entry: + br label %bb2 + +bb2: ; preds = %bb, %entry + %sdata.0 = phi i32 [ 1, %entry ], [ %ins10, %bb ] ; [#uses=2] + %b.0 = phi i32 [ 0, %entry ], [ %t0, %bb ] ; [#uses=2] + %tmp6 = trunc i32 %sdata.0 to i8 ; [#uses=2] + %t2 = and i8 %tmp6, 1 ; [#uses=1] + %t3 = icmp eq i8 %t2, 0 ; [#uses=1] + %t4 = xor i8 %tmp6, 1 ; [#uses=1] + %tmp8 = zext i8 %t4 to i32 ; [#uses=1] + %mask9 = and i32 %sdata.0, -256 ; [#uses=1] + %ins10 = or i32 %tmp8, %mask9 ; [#uses=1] + br i1 %t3, label %bb3, label %bb + +bb: ; preds = %bb2 + %t0 = add i32 %b.0, 1 ; [#uses=3] + %t1 = icmp sgt i32 %t0, 100 ; [#uses=1] + br i1 %t1, label %bb3, label %bb2 + +bb3: ; preds = %bb, %bb2 + %b.1 = phi i32 [ %t0, %bb ], [ %b.0, %bb2 ] ; [#uses=1] + %t5 = icmp eq i32 %b.1, 1 ; [#uses=1] + br i1 %t5, label %bb5, label %bb4 + +bb4: ; preds = %bb3 + tail call void @abort() noreturn nounwind + unreachable + +bb5: ; preds = %bb3 + ret i32 0 +} + +declare void @llvm.memset.i64(i8* nocapture, i8, i64, i32) nounwind + +declare void @abort() noreturn nounwind