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| author | Sanjay Patel <spatel@rotateright.com> | 2018-11-20 17:34:59 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2018-11-20 17:34:59 +0000 |
| commit | 14ab9170b8026b24a7d88bbab33e6e4494d55fa7 (patch) | |
| tree | 6ce3fc66aeb6087ef22c98530fe3003711a9e323 /llvm | |
| parent | 2778f56a40dba2efd6da9466a1405b4a097fb0b5 (diff) | |
| download | bcm5719-llvm-14ab9170b8026b24a7d88bbab33e6e4494d55fa7.tar.gz bcm5719-llvm-14ab9170b8026b24a7d88bbab33e6e4494d55fa7.zip | |
[InstSimplify] fold funnel shifts with undef operands
Splitting these off from the D54666.
Patch by: nikic (Nikita Popov)
llvm-svn: 347332
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Analysis/InstructionSimplify.cpp | 11 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstSimplify/call.ll | 12 |
2 files changed, 14 insertions, 9 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index 599a2f2ce4c..9fc10af9668 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -5042,7 +5042,16 @@ static Value *simplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd, } case Intrinsic::fshl: case Intrinsic::fshr: { - Value *ShAmtArg = ArgBegin[2]; + Value *Op0 = ArgBegin[0], *Op1 = ArgBegin[1], *ShAmtArg = ArgBegin[2]; + + // If both operands are undef, the result is undef. + if (match(Op0, m_Undef()) && match(Op1, m_Undef())) + return UndefValue::get(F->getReturnType()); + + // If shift amount is undef, assume it is zero. + if (match(ShAmtArg, m_Undef())) + return ArgBegin[IID == Intrinsic::fshl ? 0 : 1]; + const APInt *ShAmtC; if (match(ShAmtArg, m_APInt(ShAmtC))) { // If there's effectively no shift, return the 1st arg or 2nd arg. diff --git a/llvm/test/Transforms/InstSimplify/call.ll b/llvm/test/Transforms/InstSimplify/call.ll index 4207a27fd36..b3a2f96870e 100644 --- a/llvm/test/Transforms/InstSimplify/call.ll +++ b/llvm/test/Transforms/InstSimplify/call.ll @@ -632,8 +632,7 @@ define <2 x i8> @fshr_zero_shift_guard_splat(<2 x i8> %x, <2 x i8> %y, <2 x i8> define i8 @fshl_ops_undef(i8 %shamt) { ; CHECK-LABEL: @fshl_ops_undef( -; CHECK-NEXT: [[R:%.*]] = call i8 @llvm.fshl.i8(i8 undef, i8 undef, i8 [[SHAMT:%.*]]) -; CHECK-NEXT: ret i8 [[R]] +; CHECK-NEXT: ret i8 undef ; %r = call i8 @llvm.fshl.i8(i8 undef, i8 undef, i8 %shamt) ret i8 %r @@ -641,8 +640,7 @@ define i8 @fshl_ops_undef(i8 %shamt) { define i9 @fshr_ops_undef(i9 %shamt) { ; CHECK-LABEL: @fshr_ops_undef( -; CHECK-NEXT: [[R:%.*]] = call i9 @llvm.fshr.i9(i9 undef, i9 undef, i9 [[SHAMT:%.*]]) -; CHECK-NEXT: ret i9 [[R]] +; CHECK-NEXT: ret i9 undef ; %r = call i9 @llvm.fshr.i9(i9 undef, i9 undef, i9 %shamt) ret i9 %r @@ -652,8 +650,7 @@ define i9 @fshr_ops_undef(i9 %shamt) { define i8 @fshl_shift_undef(i8 %x, i8 %y) { ; CHECK-LABEL: @fshl_shift_undef( -; CHECK-NEXT: [[R:%.*]] = call i8 @llvm.fshl.i8(i8 [[X:%.*]], i8 [[Y:%.*]], i8 undef) -; CHECK-NEXT: ret i8 [[R]] +; CHECK-NEXT: ret i8 [[X:%.*]] ; %r = call i8 @llvm.fshl.i8(i8 %x, i8 %y, i8 undef) ret i8 %r @@ -661,8 +658,7 @@ define i8 @fshl_shift_undef(i8 %x, i8 %y) { define i9 @fshr_shift_undef(i9 %x, i9 %y) { ; CHECK-LABEL: @fshr_shift_undef( -; CHECK-NEXT: [[R:%.*]] = call i9 @llvm.fshr.i9(i9 [[X:%.*]], i9 [[Y:%.*]], i9 undef) -; CHECK-NEXT: ret i9 [[R]] +; CHECK-NEXT: ret i9 [[Y:%.*]] ; %r = call i9 @llvm.fshr.i9(i9 %x, i9 %y, i9 undef) ret i9 %r |
