1Pull in r199187 from upstream llvm trunk (by Jakob Stoklund Olesen): 2 3 Always let value types influence register classes. 4 5 When creating a virtual register for a def, the value type should be 6 used to pick the register class. If we only use the register class 7 constraint on the instruction, we might pick a too large register class. 8 9 Some registers can store values of different sizes. For example, the x86 10 xmm registers can hold f32, f64, and 128-bit vectors. The three 11 different value sizes are represented by register classes with identical 12 register sets: FR32, FR64, and VR128. These register classes have 13 different spill slot sizes, so it is important to use the right one. 14 15 The register class constraint on an instruction doesn't necessarily care 16 about the size of the value its defining. The value type determines 17 that. 18 19 This fixes a problem where InstrEmitter was picking 32-bit register 20 classes for 64-bit values on SPARC. 21 22Introduced here: http://svnweb.freebsd.org/changeset/base/262261 23 24Index: test/CodeGen/SPARC/spillsize.ll 25=================================================================== 26--- test/CodeGen/SPARC/spillsize.ll 27+++ test/CodeGen/SPARC/spillsize.ll 28@@ -0,0 +1,25 @@ 29+; RUN: llc < %s -verify-machineinstrs | FileCheck %s 30+target datalayout = "E-m:e-i64:64-n32:64-S128" 31+target triple = "sparcv9" 32+ 33+; CHECK-LABEL: spill4 34+; This function spills two values: %p and the materialized large constant. 35+; Both must use 8-byte spill and fill instructions. 36+; CHECK: stx %{{..}}, [%fp+ 37+; CHECK: stx %{{..}}, [%fp+ 38+; CHECK: ldx [%fp+ 39+; CHECK: ldx [%fp+ 40+define void @spill4(i64* nocapture %p) { 41+entry: 42+ %val0 = load i64* %p 43+ %cmp0 = icmp ult i64 %val0, 385672958347594845 44+ %cm80 = zext i1 %cmp0 to i64 45+ store i64 %cm80, i64* %p, align 8 46+ tail call void asm sideeffect "", "~{i0},~{i1},~{i2},~{i3},~{i4},~{i5},~{g2},~{g3},~{g4},~{g5},~{l0},~{l1},~{l2},~{l3},~{l4},~{l5},~{l6},~{l7},~{o0},~{o1},~{o2},~{o3},~{o4},~{o5},~{o7}"() 47+ %arrayidx1 = getelementptr inbounds i64* %p, i64 1 48+ %val = load i64* %arrayidx1 49+ %cmp = icmp ult i64 %val, 385672958347594845 50+ %cm8 = select i1 %cmp, i64 10, i64 20 51+ store i64 %cm8, i64* %arrayidx1, align 8 52+ ret void 53+} 54Index: lib/CodeGen/SelectionDAG/InstrEmitter.cpp 55=================================================================== 56--- lib/CodeGen/SelectionDAG/InstrEmitter.cpp 57+++ lib/CodeGen/SelectionDAG/InstrEmitter.cpp 58@@ -220,10 +220,19 @@ void InstrEmitter::CreateVirtualRegisters(SDNode * 59 unsigned VRBase = 0; 60 const TargetRegisterClass *RC = 61 TRI->getAllocatableClass(TII->getRegClass(II, i, TRI, *MF)); 62- // If the register class is unknown for the given definition, then try to 63- // infer one from the value type. 64- if (!RC && i < NumResults) 65- RC = TLI->getRegClassFor(Node->getSimpleValueType(i)); 66+ // Always let the value type influence the used register class. The 67+ // constraints on the instruction may be too lax to represent the value 68+ // type correctly. For example, a 64-bit float (X86::FR64) can't live in 69+ // the 32-bit float super-class (X86::FR32). 70+ if (i < NumResults && TLI->isTypeLegal(Node->getSimpleValueType(i))) { 71+ const TargetRegisterClass *VTRC = 72+ TLI->getRegClassFor(Node->getSimpleValueType(i)); 73+ if (RC) 74+ VTRC = TRI->getCommonSubClass(RC, VTRC); 75+ if (VTRC) 76+ RC = VTRC; 77+ } 78+ 79 if (II.OpInfo[i].isOptionalDef()) { 80 // Optional def must be a physical register. 81 unsigned NumResults = CountResults(Node); 82