diff options
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 19 | ||||
| -rw-r--r-- | llvm/test/CodeGen/AArch64/aarch64-dynamic-stack-layout.ll | 10 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/win64_frame.ll | 5 |
3 files changed, 22 insertions, 12 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 32a0bf6b2d1..f6a12d270c0 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -2356,15 +2356,24 @@ void SelectionDAG::computeKnownBits(SDValue Op, APInt &KnownZero, // Output known-0 bits are known if clear or set in both the low clear bits // common to both LHS & RHS. For example, 8+(X<<3) is known to have the // low 3 bits clear. + // Output known-0 bits are also known if the top bits of each input are + // known to be clear. For example, if one input has the top 10 bits clear + // and the other has the top 8 bits clear, we know the top 7 bits of the + // output must be clear. computeKnownBits(Op.getOperand(0), KnownZero2, KnownOne2, Depth+1); - unsigned KnownZeroOut = KnownZero2.countTrailingOnes(); + unsigned KnownZeroHigh = KnownZero2.countLeadingOnes(); + unsigned KnownZeroLow = KnownZero2.countTrailingOnes(); computeKnownBits(Op.getOperand(1), KnownZero2, KnownOne2, Depth+1); - KnownZeroOut = std::min(KnownZeroOut, + KnownZeroHigh = std::min(KnownZeroHigh, + KnownZero2.countLeadingOnes()); + KnownZeroLow = std::min(KnownZeroLow, KnownZero2.countTrailingOnes()); if (Op.getOpcode() == ISD::ADD) { - KnownZero |= APInt::getLowBitsSet(BitWidth, KnownZeroOut); + KnownZero |= APInt::getLowBitsSet(BitWidth, KnownZeroLow); + if (KnownZeroHigh > 1) + KnownZero |= APInt::getHighBitsSet(BitWidth, KnownZeroHigh - 1); break; } @@ -2372,8 +2381,8 @@ void SelectionDAG::computeKnownBits(SDValue Op, APInt &KnownZero, // information if we know (at least) that the low two bits are clear. We // then return to the caller that the low bit is unknown but that other bits // are known zero. - if (KnownZeroOut >= 2) // ADDE - KnownZero |= APInt::getBitsSet(BitWidth, 1, KnownZeroOut); + if (KnownZeroLow >= 2) // ADDE + KnownZero |= APInt::getBitsSet(BitWidth, 1, KnownZeroLow); break; } case ISD::SREM: diff --git a/llvm/test/CodeGen/AArch64/aarch64-dynamic-stack-layout.ll b/llvm/test/CodeGen/AArch64/aarch64-dynamic-stack-layout.ll index a31c66bad4b..f33211eadd2 100644 --- a/llvm/test/CodeGen/AArch64/aarch64-dynamic-stack-layout.ll +++ b/llvm/test/CodeGen/AArch64/aarch64-dynamic-stack-layout.ll @@ -255,7 +255,7 @@ entry: ; CHECK: ubfx x9, x0, #0, #32 ; CHECK: lsl x9, x9, #2 ; CHECK: add x9, x9, #15 -; CHECK: and x9, x9, #0xfffffffffffffff0 +; CHECK: and x9, x9, #0x7fffffff0 ; CHECK: mov x10, sp ; CHECK: sub x[[VLASPTMP:[0-9]+]], x10, x9 ; CHECK: mov sp, x[[VLASPTMP]] @@ -302,7 +302,7 @@ entry: ; CHECK: ubfx x9, x0, #0, #32 ; CHECK: lsl x9, x9, #2 ; CHECK: add x9, x9, #15 -; CHECK: and x9, x9, #0xfffffffffffffff0 +; CHECK: and x9, x9, #0x7fffffff0 ; CHECK: mov x10, sp ; CHECK: sub x[[VLASPTMP:[0-9]+]], x10, x9 ; CHECK: mov sp, x[[VLASPTMP]] @@ -364,7 +364,7 @@ entry: ; CHECK: ubfx x9, x0, #0, #32 ; CHECK: lsl x9, x9, #2 ; CHECK: add x9, x9, #15 -; CHECK: and x9, x9, #0xfffffffffffffff0 +; CHECK: and x9, x9, #0x7fffffff0 ; CHECK: mov x10, sp ; CHECK: sub x[[VLASPTMP:[0-9]+]], x10, x9 ; CHECK: mov sp, x[[VLASPTMP]] @@ -417,7 +417,7 @@ entry: ; CHECK: ubfx x9, x0, #0, #32 ; CHECK: lsl x9, x9, #2 ; CHECK: add x9, x9, #15 -; CHECK: and x9, x9, #0xfffffffffffffff0 +; CHECK: and x9, x9, #0x7fffffff0 ; CHECK: mov x10, sp ; CHECK: sub x[[VLASPTMP:[0-9]+]], x10, x9 ; CHECK: mov sp, x[[VLASPTMP]] @@ -468,7 +468,7 @@ entry: ; CHECK: ubfx x9, x0, #0, #32 ; CHECK: lsl x9, x9, #2 ; CHECK: add x9, x9, #15 -; CHECK: and x9, x9, #0xfffffffffffffff0 +; CHECK: and x9, x9, #0x7fffffff0 ; CHECK: mov x10, sp ; CHECK: sub x[[VLASPTMP:[0-9]+]], x10, x9 ; CHECK: mov sp, x[[VLASPTMP]] diff --git a/llvm/test/CodeGen/X86/win64_frame.ll b/llvm/test/CodeGen/X86/win64_frame.ll index 2c62f4918a7..477b3144d9e 100644 --- a/llvm/test/CodeGen/X86/win64_frame.ll +++ b/llvm/test/CodeGen/X86/win64_frame.ll @@ -100,8 +100,9 @@ define i32 @f8(i32 %a, i32 %b, i32 %c, i32 %d, i32 %e) "no-frame-pointer-elim"=" alloca i32, i32 %a ; CHECK: movl %ecx, %eax - ; CHECK: leaq 15(,%rax,4), %rax - ; CHECK: andq $-16, %rax + ; CHECK: leaq 15(,%rax,4), %rcx + ; CHECK: movabsq $34359738352, %rax + ; CHECK: andq %rcx, %rax ; CHECK: callq __chkstk ; CHECK: subq %rax, %rsp |
