Index: lib/Target/AMDGPU/SIFoldOperands.cpp =================================================================== --- lib/Target/AMDGPU/SIFoldOperands.cpp +++ lib/Target/AMDGPU/SIFoldOperands.cpp @@ -653,6 +653,7 @@ // again. The same constant folded instruction could also have a second // use operand. NextUse = MRI->use_begin(Dst.getReg()); + FoldList.clear(); continue; } Index: test/CodeGen/MIR/AMDGPU/fold-multiple.mir =================================================================== --- /dev/null +++ test/CodeGen/MIR/AMDGPU/fold-multiple.mir @@ -0,0 +1,59 @@ +# RUN: llc --mtriple=amdgcn--amdhsa -mcpu=fiji -verify-machineinstrs -run-pass si-fold-operands,si-shrink-instructions %s -o - | FileCheck %s +--- | + define amdgpu_kernel void @test() #0 { + ret void + } + + attributes #0 = { nounwind } + +... +--- + +# This used to crash / trigger an assertion, because re-scanning the use list +# after constant-folding the definition of %3 lead to the definition of %2 +# being processed twice. + +# CHECK-LABEL: name: test +# CHECK: %2 = V_LSHLREV_B32_e32 2, killed %0, implicit %exec +# CHECK: %4 = V_AND_B32_e32 8, killed %2, implicit %exec + +name: test +alignment: 0 +exposesReturnsTwice: false +legalized: false +regBankSelected: false +selected: false +tracksRegLiveness: true +registers: + - { id: 0, class: vgpr_32 } + - { id: 1, class: sreg_32 } + - { id: 2, class: vgpr_32 } + - { id: 3, class: sreg_32 } + - { id: 4, class: vgpr_32 } + - { id: 5, class: sreg_128 } +frameInfo: + isFrameAddressTaken: false + isReturnAddressTaken: false + hasStackMap: false + hasPatchPoint: false + stackSize: 0 + offsetAdjustment: 0 + maxAlignment: 0 + adjustsStack: false + hasCalls: false + maxCallFrameSize: 0 + hasOpaqueSPAdjustment: false + hasVAStart: false + hasMustTailInVarArgFunc: false +body: | + bb.0 (%ir-block.0): + %0 = IMPLICIT_DEF + %1 = S_MOV_B32 2 + %2 = V_LSHLREV_B32_e64 %1, killed %0, implicit %exec + %3 = S_LSHL_B32 %1, killed %1, implicit-def dead %scc + %4 = V_AND_B32_e64 killed %2, killed %3, implicit %exec + %5 = IMPLICIT_DEF + BUFFER_STORE_DWORD_OFFSET killed %4, killed %5, 0, 0, 0, 0, 0, implicit %exec :: (volatile store 2 into `half addrspace(1)* undef`) + S_ENDPGM + +...