diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/IndVarSimplify.cpp | 7 | ||||
| -rw-r--r-- | llvm/test/Transforms/IndVarSimplify/lftr_disabled.ll | 28 |
2 files changed, 34 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp index 9a7882211ba..10782963177 100644 --- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -86,6 +86,10 @@ static cl::opt<bool> UsePostIncrementRanges( cl::desc("Use post increment control-dependent ranges in IndVarSimplify"), cl::init(true)); +static cl::opt<bool> +DisableLFTR("disable-lftr", cl::Hidden, cl::init(false), + cl::desc("Disable Linear Function Test Replace optimization")); + namespace { struct RewritePhi; @@ -2413,7 +2417,8 @@ bool IndVarSimplify::run(Loop *L) { // If we have a trip count expression, rewrite the loop's exit condition // using it. We can currently only handle loops with a single exit. - if (canExpandBackedgeTakenCount(L, SE, Rewriter) && needsLFTR(L, DT)) { + if (!DisableLFTR && canExpandBackedgeTakenCount(L, SE, Rewriter) && + needsLFTR(L, DT)) { PHINode *IndVar = FindLoopCounter(L, BackedgeTakenCount, SE, DT); if (IndVar) { // Check preconditions for proper SCEVExpander operation. SCEV does not diff --git a/llvm/test/Transforms/IndVarSimplify/lftr_disabled.ll b/llvm/test/Transforms/IndVarSimplify/lftr_disabled.ll new file mode 100644 index 00000000000..c647d123dd7 --- /dev/null +++ b/llvm/test/Transforms/IndVarSimplify/lftr_disabled.ll @@ -0,0 +1,28 @@ +; LFTR should not eliminate the need for the computation of i*i completely +; due to LFTR is disabled. +; RUN: opt < %s -indvars -dce -disable-lftr -S | FileCheck %s + +; Provide legal integer types. +target datalayout = "n8:16:32:64" + + +@A = external global i32 ; <i32*> [#uses=1] + +define i32 @quadratic_setlt() { +; CHECK-LABEL: @quadratic_setlt( +; CHECK: mul +entry: + br label %loop + +loop: ; preds = %loop, %entry + %i = phi i32 [ 7, %entry ], [ %i.next, %loop ] ; <i32> [#uses=5] + %i.next = add i32 %i, 1 ; <i32> [#uses=1] + store i32 %i, i32* @A + %i2 = mul i32 %i, %i ; <i32> [#uses=1] + %c = icmp slt i32 %i2, 1000 ; <i1> [#uses=1] + br i1 %c, label %loop, label %loopexit + +loopexit: ; preds = %loop + ret i32 %i +} + |
