41647412c6
In PowerPC, if a borrow occurs during a subtraction, the carry bit is zero (unset). The carry bit is set if no borrow occurs. For ISD::USUBO_CARRY, the nodes produce two results: the normal result of the addition or subtraction, and a boolean value that is 1 if and only if there is an outgoing carry or borrow. Therefore, we need to convert a 1 (which indicates a borrow in ISD::USUBO_CARRY) to 0 to match PowerPC's definition of borrow. Similarly, we need to convert a 0 (no borrow in ISD::USUBO_CARRY) to 1 for PowerPC. To perform this conversion, we use XOR 1 instead of XOR DAG.getAllOnesConstant(DL, CarryOp.getValueType()). `
33 lines
1022 B
LLVM
33 lines
1022 B
LLVM
; RUN: llc -ppc-asm-full-reg-names -verify-machineinstrs \
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; RUN: -mtriple=powerpc-ibm-aix -mcpu=pwr7 < %s | FileCheck %s
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define i64 @foo(i32 noundef %argc) #0 {
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entry:
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%argc.addr = alloca i32, align 4
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%num = alloca i64, align 8
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store i32 %argc, ptr %argc.addr, align 4
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%0 = load i32, ptr %argc.addr, align 4
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%sub = sub nsw i32 %0, 2
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%conv = sext i32 %sub to i64
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store i64 %conv, ptr %num, align 8
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%1 = load i64, ptr %num, align 8
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%sub1 = sub nsw i64 0, %1
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ret i64 %sub1
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}
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attributes #0 = { noinline nounwind optnone "frame-pointer"="all" "stack-protector-buffer-size"="8" }
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; CHECK: .foo:
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; CHECK-NEXT: # %bb.0: # %entry
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; CHECK-NEXT: stw r3, -8(r1)
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; CHECK-NEXT: lwz r3, -8(r1)
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; CHECK-NEXT: addi r3, r3, -2
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; CHECK-NEXT: srawi r4, r3, 31
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; CHECK-NEXT: stw r3, -12(r1)
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; CHECK-NEXT: stw r4, -16(r1)
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; CHECK-NEXT: lwz r3, -16(r1)
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; CHECK-NEXT: lwz r4, -12(r1)
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; CHECK-NEXT: subfic r4, r4, 0
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; CHECK-NEXT: subfze r3, r3
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; CHECK-NEXT: blr
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